Theblue screen of death (BSoD) – orblue screen error,blue screen,fatal error,bugcheck, and officially known as astop error[1][2][3] – is acritical error screen displayed by many iterations ofMicrosoft Windowsoperating systems. It is used to indicate asystem crash, in which the operating system reaches a critical condition where it can no longer operate safely. Its name comes from the blue colored background used predominately on the error screens found in the majority of Windows releases, which was changed to black starting withWindows 11 version 24H2.
Possible issues contributing to a BSoD may include hardware failures, an issue with or without a device driver,viruses,malware, and other factors such as intentional user action.
Blue screen errors have been around since the first version of Windows in 1985. In the Beta Release ofWindows 1.0, if it detects a version ofDOS that is newer than the OS expects, the boot screen would have the text "Incorrect DOS version" alongside other messages detailing what check failed to pass appended into it before starting normally.[4] This behavior remains in the final version released to retail (version 1.01); however, the remaining text messages were removed during development in the lead up to Windows 1.0's release, displayingmojibake instead.[4] However, this is not a screen of death; when the operating system actually crashes, it either freezes or unexpectedly exits to DOS. This behavior is also present inWindows 2.0 andWindows 2.1.[citation needed]
Windows 3.0 uses a text-mode screen for displaying important system messages, usually from digital device drivers in386 Enhanced Mode or other situations where a program could not run.Windows 3.1 changed the color of this screen from black to blue. It also displays a blue screen when the user presses theCtrl+Alt+Delete key combination to bring up a rudimentarytask manager, reserved for quitting any unresponsive programs if they are available. Like previous versions of Windows, Windows 3.x exits to DOS if an error condition is severe enough.[citation needed]
The first BSoD to indicate a critical system error appeared inWindows NT 3.1 (the first version of theWindows NT family, released in 1993) and all subsequent releases.[5] The error screens initially started with*** STOP: in its earlier iterations, hence it became known as a "stop error." This format was used onall Windows operating systems released afterwards, with various differences in later versions. Despite popular belief, there are no known genuine equivalents of a BSoD in theWindows Embedded Compact (formerly known as Windows CE) line of embedded operating systems.[6]
BSoDs can be caused by poorly writtendevice drivers or malfunctioning hardware,[7] such as faultymemory, power supply problems, overheating of components, hardware running beyond its specification limits, or evenACPI compliance issues with theBIOS.[8] In theWindows 9x line of operating systems, incompatibleDLLs or bugs in the operating systemkernel could also cause BSoDs.[9] Because of the general instability and lack of memory protection in Windows 9x, BSoDs were much more common.[citation needed]
On June 26, 2025, Microsoft announced that the color of the blue screen of death would be officially changed to black alongside an overhaul of the design of the screen itself which will be present inWindows 11 version 24H2,[10][11][12] saying that the new design will be "easier to navigate unexpected restarts and faster recoveries".[13] Previously, this color change appeared on a few builds of Windows 11 (including theRTM) before reverting to a more different shade of blue in later builds prior to Windows 11 version 24H2. Notably, this change was made nearly a year after the2024 CrowdStrike outages in July 2024, which caused blue screens to many computers in the business and enterprise segments running Windows due to an update bug.[10]
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On September 4, 2014, several online journals such asBusiness Insider,DailyTech,Engadget,Gizmodo,Lifehacker,Neowin,Softpedia,TechSpot,Boy Genius Report (BGR),The Register, andThe Verge,[14] as well as print and non-English sources likePC Authority and Austrian tech siteFutureZone[15] all attributed the creation of the blue screen of death toSteve Ballmer, the formerCEO of Microsoft. The articles specifically cited a blog post by Microsoft employeeRaymond Chen entitled "Who wrote the text for the Ctrl+Alt+Del dialog in Windows 3.1?",[16] which focused on the creation of thefirst rudimentary task manager in Windows 3.x. The aforementioned task manager shared some visual similarities with a BSOD, with Ballmer writing the messages that appeared on the screen.[16]
Chen took notice of the widespread misinformation and addressed the issue himself in a blog post on September 9, 2014. According to Chen, he was scathing on his evaluation of major tech news sites that had picked up on the incorrect story and performed poor or non-existent research that demonstrated complete ignorance of his original account. He indicated that, in addition to the faulty base story, over half a dozen significant sites had included other embellished or invented details in their stories, including incorrectly naming Chen as a Microsoft executive, treating Chen as an "official company spokesperson", and using unrelated images from Windows NT or Windows 95 as illustrations. In addition, he also pointed out a very special mention for the worst single distortion out of any misinformations, which belonged toBGR (Boy Genius Report), who "fabricated a scenario and posited it as real" in a rhetorical question to readers. He also found that several sources had conflated the creation of the BSoD with the fact that they occur, thus invertingcause and effect by implying that the invention of BSoDscaused fatal errors to occur instead of their actual, helpful function of giving the user information about a fatal errorafter the system has already become unrecoverable (such incorrect sources transitively blamed Ballmer for the existence of all fatal crashes in Windows).[17] A day after his initial complaint, Chen would follow this up with another blog post on September 10, 2014, claiming responsibility for revising the BSoD inWindows 95. His post said in detail that he was the one who "sort of" created the BSoD in its first modern incarnation in Windows 95.[18]
According to former Microsoft employeeDave Plummer, the BSoD in theWindows NT family was not based on the rudimentary task manager screen of Windows 3.x, but was actually designed by Microsoft developer John Vert.[19] Additionally, Vert has also stated the reason why the error screens were given the color blue was because the universal color palette of the video hardware at that time was very rudimentary, and he personally used aMIPS OS box andSlickEdit for programming so that both the firmware and editor displayed white text on a blue background, making for a more consistent programming experience.[19]
BSoDs originally showedsilver (HTML color #A8A8A8) (and laterwhite (HTML color #FFFFFF)) text on aroyal blue (HTML color #0000A8 for Windows NT 3.1/3.5/3.51/4.0; HTML color #000080 for Windows 2000/XP/Vista/7) background with information about current memory values and register values. Starting with Windows Server 2012 (released in September 2012), Windows adopted acerulean background (HTML color #1A67B3 for Windows 8/8.1 to Windows 10 version 1151; HTML color #0078D7 for Windows 10 versions 1607 to 22H2). Earlier versions ofWindows 11 used a black background,[20] which was changed to dark blue starting with build 22000.348[21] and then back to black with build 26120.3653.[22][20] Preview builds of Windows 10, Windows 11, andWindows Server (available from theWindows Insider program) feature a dark green (HTML color #246F24) background instead of a blue one.[23][24] Windows 3.1, 95, and98 supports customizing the color of the screen[25] whereas the color was hard-coded in theWindows NT family.[25]
Windows 95, 98, andMe render their BSoDs in the 80×25text mode with a 720×400screen resolution. BSoDs in the Windows NT family initially used the 80×50 text mode with a 720×400 screen resolution, but were displayed in a 640×480 screen resolution starting with Windows 2000. BSoDs from Windows 8 and Windows Server 2012 onwards are rendered in higher resolutions than previous versions of Windows, specifically the highest screen resolution available on UEFI machines. On legacy BIOS machines, they use the 1024×768 resolution by default, but they can also be configured to use the highest resolution exposed by the firmware (via thehighestmode parameter inBoot Configuration Data).[26] Windows 95, 98, Me, and NT versions prior to Windows 2000 used text mode fonts provided by the graphics adapter; Windows 2000, XP, Vista and 7 used kernel mode fonts provided by the kernel's boot video driverbootvid.dll, which is a text mode-like font used in Windows 2000 andLucida Console in Windows XP to 7; and Windows 8 and Windows Server 2012 onwards use theSegoe UI font.[citation needed]
Windows 10 builds 14316 and up uses the same format as Windows 8, but has aQR code which leads to a Microsoft Support web page that tries to help users troubleshoot the issue step-by-step. This format was retained in Windows 11, however build 26120.3291 onwards changes the layout to be more consistent with that of Windows 11's UI, removing the QR code among other changes.[22][20]
In theWindows NT family of operating systems, the blue screen of death (referred to as "bug check" in the Windowssoftware development kit and driver development kit documentation) occurs when the kernel or a driver running inkernel mode encounters an error from which it cannot recover. This was usually caused by anillegal operation being performed. The only safe action the operating system can take in this situation was torestart the computer. Because of this, data loss may occur since the restart was unplanned, and the user was not given an opportunity to save their work.[citation needed]
The text on the error screen contains the code of the error and its symbolic name (e.g.0x0000001E (KMODE_EXCEPTION_NOT_HANDLED)) along with four error-dependent values in parentheses that are there to help software engineers fix the problem that occurred. Depending on the error code, it may display the address where the problem occurred, along with the driver which was loaded at that address. Under Windows NT, the second and third sections of the screen may contain information on all loaded drivers and a stack dump, respectively. The driver information was in three columns; the first lists the base address of the driver, the second lists the driver's creation date (as aUnix timestamp), and the third lists the name of the driver.[27] By default, Windows will create amemory dump file when a stop error occurs. Depending on the OS version, there may be several formats this can be saved in, ranging from a 64kB "minidump" (introduced in Windows 2000) to a "complete dump" which was effectively a copy of the entire contents of physical memory (RAM). The resulting memory dump file may be debugged later, using a kerneldebugger. For Windows, WinDBG or KD debuggers fromDebugging Tools for Windows are used.[28] A debugger was necessary to obtain astack trace, and may be required to ascertain the true cause of the problem; as the information on-screen was limited and thus possibly misleading, it may hide the true source of the error. By default, Windows XP was configured to save only a 64kB minidump when it encounters a stop error, and to then automatically reboot the computer. Because this process happens very quickly, the blue screen may be seen only for an instant or not at all. Users have sometimes noted this as arandom reboot rather than a traditional stop error, and are only aware of an issue after Windows reboots and displays a notification that it has recovered from a serious error. This happens only when the computer has a function called "Auto Restart" enabled, which can be disabled in the Control Panel which in turn shows the stop error.[citation needed]
Microsoft Windows can also be configured to send live debugging information to a kernel debugger running on a separatecomputer. If a stop error was encountered while a live kernel debugger was attached to the system, Windows will halt execution and cause the debugger to break in, rather than displaying the BSoD. The debugger can then be used to examine the contents of memory and determine the source of the problem.[citation needed]
A BSoD can also be caused by a critical boot loader error, where the operating system was unable to access the boot partition due to incorrect storage drivers, a damaged file system or similar problems. The error code in this situation wasSTOP: 0x0000007B (INACCESSIBLE_BOOT_DEVICE).[29] In such cases, there was no memory dump saved. Since the system was unable to boot from the hard drive in this situation, correction of the problem often requires using the repair tools found on the Windows installation disc.[citation needed]
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BSoDs in the Windows NT family before the release ofWindows 8 andWindows Server 2012 displayed the error name in uppercase (e.g.APC_INDEX_MISMATCH) and its respective hexadecimal error number (e.g.0x00000001), along with four parameters. This was shown together in the following format:[30]
error code (parameter 1, parameter 2, parameter 3, parameter 4)
error name
Depending on the error number and its nature, all, some, or even none of the parameters contain data pertaining to what went wrong, and/or where it happened. In addition, starting withWindows 2000 onwards, the error screens showed up to four paragraphs of general explanation and advice and may have included other technical data such the file name of the culprit and memory addresses.
The following is a re-creation of the BSoD from Windows 2000, although they somewhat vary:
*** STOP: 0x00000001 (0x00000000,0x00000000,0x00000000,0x00000000)APC_INDEX_MISMATCHIf this is the first time you've seen this Stop error screen,restart your computer. If this screen appears again, followthese steps:Check to make sure any new hardware or software is properly installed.If this is a new installation, ask your hardware or software manufacturerfor any Windows 2000 updates you might need.If problems continue, disable or remove any newly installed hardwareor software. Disable BIOS memory options such as caching or shadowing.If you need to use Safe Mode to remove or disable components, restartyour computer, press F8 to select Advanced Startup Options, and thenselect Safe Mode.Refer to your Getting Started manual for more information ontroubleshooting Stop errors.
In rare cases, the BSOD would be truncated, sometimes not showing the error name, codes, or the four paragraphs of advice. Instead, it would often show different formats of the error screen depending on the type of error that occurred. For instance, BSoDs related to the termination of theWinlogon process (e.g. "0xC000021A (WINLOGON_FATAL_ERROR)") displayed the following message in this format:[31]
STOP: c000021a {Fatal System Error}The Windows Logon Process/SubSystem system process terminated unexpectedlywith a status of parameter 1 (parameter 2 parameter 3).The system has been shut down.On Windows 2000, the above message was sometimes displayed alongside the four paragraphs of general instructions and advice, the latter of which is absent on Windows XP to Windows 7.
Another example was that when Windows finds a corrupt registry file that was critical to the operating system (e.g. "0xC0000218 (STATUS_CANNOT_LOAD_REGISTRY_FILE)"), it would display the following message:
STOP: c0000218 {Registry File Failure}The registry cannot load the hive(file):\SystemRoot\System\Config\SOFTWAREor its log or alternate.It is corrupt, absent, or not writable.Also, hardware errors that can prevent Windows from booting properly will also display this rare message (This example is0x00000080 (NMI_HARDWARE_FAILURE); note that the error code is not shown in this example below):
Hardware MalfunctionCall your hardware vendor for support.NMI: Parity Check / Memory Parity ErrorThe system has halted.
Certain error codes would contain descriptions that were used on the BSoD in lieu of the error name, describing what kind of error that has happened. For example, BSoDs with error code0x000000F4 (CRITICAL_OBJECT_TERMINATION) originally read "A process or thread crucial to system operation has unexpectedly exited or been terminated", and BSoDs with error code0x000000E2 (MANUALLY_INITIATED_CRASH) originally read "The user manually initiated the crash dump".
With the release ofWindows XP, the layout of the BSoD was slightly altered, which would remain in use for subsequent versions of Windows untilWindows 8. Specifically, the hexadecimal error number and the four parameters were moved to the bottom of the screen after the four paragraphs under the label "Technical information:". The message about referring the user to the Getting Started manual for troubleshooting BSoDs (referred to as "stop errors") was also removed, and references to Windows 2000 were shortened to simply say Windows. The error screens also began with the now-infamous message:
A problem has been detected and Windows has been shut down to prevent damageto your computer.
The following is a re-creation of the BSoD from Windows XP to Windows 7, although they somewhat vary:
A problem has been detected and Windows has been shut down to prevent damageto your computer.APC_INDEX_MISMATCHIf this is the first time you've seen this Stop error screen,restart your computer. If this screen appears again, followthese steps:Check to make sure any new hardware or software is properly installed.If this is a new installation, ask your hardware or software manufacturerfor any Windows updates you might need.If problems continue, disable or remove any newly installed hardwareor software. Disable BIOS memory options such as caching or shadowing.If you need to use Safe Mode to remove or disable components, restartyour computer, press F8 to select Advanced Startup Options, and thenselect Safe Mode.Technical Information:*** STOP: 0x00000001 (0x00000000,0x00000000,0x00000000,0x00000000)
From Windows 2000 onwards, system memory dumps are automatically performed, usually in the form of a 64 KB "minidump" by default. When this happens, the BSoD on Windows 2000 will display the following message that replaces the four paragraphs of general instructions and advice, which can also be seen when "Write an event to the system log" and/or "Send an administrative alert" is checked in the "System Failure" section under "Startup and Recovery" in System Properties even when system memory dumps are disabled:
Beginning dump of physical memoryPhysical memory dump complete. Contact your system administrator ortechnical support group.
On Windows XP to Windows 7, the above message remains the same, but with some slight modifications, and is displayed after the four paragraphs of general advice, which were hidden on Windows 2000 when a memory dump is performed:
Beginning dump of physical memoryPhysical memory dump complete.Contact your system administrator or technical support group for furtherassistance.
Also, in most instances when performing system memory dumps on the BSoD from Windows XP to Windows 7, the following messages are displayed along with an indicator showing the progress of the memory dumps:
Collecting data for crash dump ...Initializing disk for crash dump ...Beginning dump of physical memory.Dumping physical memory to disk: 100
Upon completion of the memory dumps, the following message is then displayed on screen:
Physical memory dump complete.Contact your system admin or technical support group for further assistance.
Additionally, on versions of Windows using the 64-bit architecture, the BSoD would have the four parameters extended to sixteen digits ("0x0000000000000000") instead of eight ("0x00000000").
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With the release of Windows 8 and Windows Server 2012, the BSoD was significantly changed, removing all of the above in favor of the error name and a concise description. Windows 8 also adds a sad emoticon to the error screen, which was absent from Japanese releases or its Windows Server counterparts. The hexadecimal error code and parameters can still be found in theWindows Event Log or inmemory dumps.
The main text that is displayed on the screen by default is read as follows:
The above message can change depending on whether or not automatic restart or memory dumps are enabled or disabled. For example, if the automatic restart functionality is disabled but memory dumping is enabled, then the above message is altered to read this:
As well, if memory dumping is disabled, then the same message is altered to read this:
Then, if both the automatic restart functionality and memory dumping are disabled, then the following message would be displayed instead:
In both of these last two examples, a percentage completion (e.g. "100% complete") which shows the progress of the memory dumps being performed is absent when memory dumping is disabled.
In some cases, BSoDs would use a truncated or slightly altered format from previous BSoDs. For instance, BSoDs relating to Winlogon termination may have the aforementioned hexadecimal error code in place of the error name. Hardware errors causing an BSoD also uses the same format as the normal BSoD, including the use of the error name instead of an error code. One such example are BSoDs with the error name "NMI_HARDWARE_FAILURE" (error code0x00000080).[citation needed]
Unlike with Windows 7 and prior, error codes that had written descriptions were changed to simply use the error name due to the aforementioned changes to the format of the BSoD, for instance, the message "A process or thread crucial to system operation has unexpectedly exited or been terminated" for error code0x000000F4 was changed to use the error name "CRITICAL_OBJECT_TERMINATION".
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The format introduced with Windows Server 2012 and Windows 8 was retained in Windows 10 and Windows 11 (as well as its Server counterparts). Beginning with build 14316 of Windows 10 version 1607, aQR code was added to the screen for quick troubleshooting, while all references to the word "PC" were changed to "device" starting from Windows 10 version 2004 onwards. Build 26120.3291 of Windows 11 version 24H2 made a complete overhaul to the format of the BSoD, changing the layout to be more consistent with the design language of Windows 11 while removing the QR code and the sad emoticon completely. The hexadecimal error code (but not the parameters) returned and is shown after the error name, but without the leading zeroes (e.g.0x00000001 (APC_INDEX_MISMATCH) becoming0x01).[22][20]
TheWindows 9x line of operating systems used the blue screen of death as the main way forvirtual device drivers to report errors to the user. This version of the BSoD, internally referred to as "_VWIN32_FaultPopup", gives the user the option either to restart the computer or to terminate the current running program and continue using Windows, allowing the user to save their work before any data could be lost. Depending on the type of situation it may have occurred, however, the options to either continue or restart may or may not work at all. This is in contrast to the BSoDs in the Windows NT family, which prevented the user from using the computer until it has been powered off or restarted (usually automatic for the latter).[citation needed]
The most common BSoD was displayed on an 80×25 text-mode screen, which was the operating system's way of reporting an interrupt caused by a processor exception; it is a more serious form of thegeneral protection fault dialog boxes. The memory address of the error was given and the error type was a hexadecimal number from 00 to 11 (0 to 17 decimal). The error codes are as follows:[32]
The following situations below can cause a BSoD:
In Windows 95 and 98, a BSoD occurs when the system attempts to access the file "c:\con\con", "c:\aux\aux", or "c:\prn\prn" on the hard drive, which can be inserted on a website to crash visitors' machines as a prank. In reality, however, they arereserved device names for DOS systems; attempting to access them from Windows causes a crash, bringing up said BSoD. Creating the aforementioned directories within Windows will also not work and may cause the same BSOD to occur. On March 16, 2000, Microsoft released asecurity update to resolve this issue.[33]
One famous instance of a Windows 9x BSoD occurred during a presentation of a Windows 98beta given byBill Gates atCOMDEX on April 20, 1998: The demo PC crashed with a BSoD when his assistant,Chris Capossela, connected a scanner to the PC to demonstrate Windows 98's support forPlug and Play devices. This event brought thunderous applause from the crowd and Gates replied (after a nervous pause): "That must be why we're not shipping Windows 98 yet."[34]
Stop errors are comparable tokernel panics inmacOS,Linux, and otherUnix-like systems, and to bugchecks inOpenVMS.
Ablack screen of death can occur upon hardware or software failures.Windows 3.1 displays a black screen of death instead of a blue one.[17] Some versions of macOS (notablyOS X Lion) display a black screen of death instead of a kernel panic, usually pointed to a graphics card or sleep/wake issue,[35] it may also display a black screen when the operating system fails to boot properly.[36] TheXbox series of consoles (which includes theoriginal Xbox,Xbox 360,Xbox One and theXbox Series X/S) also display a black screen when a hardware or software error occurs.[37]
In some cases, a differently-colored error screen was used.Beta versions ofWindows 98 display a red error screen raised by theAdvanced Configuration and Power Interface (ACPI) when the host computer'sBIOS encounters a problem.[38] Thebootloader of thefirst beta version ofWindows Vista originally displayed a red screen background in the event of a boot failure,[39][40][41] which was changed to black afterwards. As mentioned earlier, theinsider builds ofWindows 10 and later, as well asWindows Server 2016 and later, display a green screen instead of blue.[23][24] Windows 10 and later (and Windows Server 2016 and later) also display an orange screen in an extremely rare case where a hardware issue with the GPU or a graphics driver problem was encountered.[42]
ReactOS, an open-source operating system designed to achieve binary compatibility with Windows, implements a version of the blue screen of death similar to that used in Windows NT operating systems.systemd, a software suite providing system components forLinux operating systems, also implements a version of the blue screen of death similar to that of Windows, albeit not as a replacement to the kernel panic in Linux (see above), but rather was used in the event of a bootup failure. This iteration uses systemd-bsod, which was added on December 6, 2023 starting with version 255 of systemd.[43][44]
In the final release of Windows, these detailed messages were hastily removed. The code that would print them; however, was not, and this is what produces the garbage output.
While Microsoft is switching to a Black Screen of Death in Windows 11, the screen is identical to the one found in Windows 10 otherwise. The sad face remains, as does the stop code and crash dump. The current preview of Windows 11 includes a green BSOD, a color that Microsoft has been using for Windows Insider builds since 2016.
BSOD stands for Blue Screen Of Death. One can customize the colors of this screen by setting a couple of variables in the 386Enh section of SYSTEM.INI: MessageTextColor and MessageBackColor. The user can only customize the BSOD under Windows 3.1, 95, and 98. These changes do not work under the Windows NT variants.
