If it works with other operating systems, I'd suggest you look for Windows help on the matter. The device obviously works well.

If it works with other operating systems, I'd suggest you look for Windows help on the matter. The device obviously works well.

That makes sense. But I have spent a lot of time to search Windows forums about this issue without any success.
In fact I think it's the Win11/ESP32 combination that is the issue. If Win11 couldn't handle Serial over bluetooth at all, this should be known!

Honestly what do you expect? This is Arduino issue repo. Since Windows 10 is working, something in Windows has changed and not working anymore. The BLE implementation is OS agnostic.

Windows 11 does BLE serial different!

Windows 11 BLE Serial Support

Windows 11 fundamentally supportsBluetooth Low Energy (BLE) starting with version 22H2 with Bluetooth Core Specification 5.3, howevernot with the classic Serial Port Profile (SPP) like Bluetooth Classic. Communication via BLE works differently than direct serial connections with Bluetooth Classic.

BLE vs. Bluetooth Classic Serial

WithBluetooth Classic, a virtual COM port is automatically created when you pair an SPP device. WithBLE, there is no native SPP support – instead, theGATT protocol (Generic Attribute Profile) is used.

BLE UART via GATT

For serial communication over BLE, GATT-based services like theNordic UART Service (NuS) are used. This emulates a UART interface via two GATT Characteristics:

• TX Characteristic (0x6E400002) with WRITE permission for data from client to server
• RX Characteristic (0x6E400003) with READ/NOTIFY permission for data from server to client

Practical Solutions

For communicating with BLE UART devices on Windows 11, there are several approaches:

Software Tools for Virtual COM Ports:

• ble-serial: A tool that connects BLE UART modules with virtual serial ports (COM ports), functioning similar torfcomm bind for Bluetooth Classic
• BLE Serial Terminal: A native Windows application for BLE UART communication that works on Windows 10 and 11

Programmatic Access:

Windows provides APIs for GATT client functionality, allowing you to communicate via BLE Characteristics. Access is through GATT Services and Characteristics instead of classic serial COM ports.

Windows 11 also supports serial over classic bluetooth (SPP). For instance it communicates well with an HC-05.
I would have liked to connect an ESP32 as easily.

I observed that an old version of espressif arduino made my SPP connection work with Windows 11.
But it was rather unstable.

I just rolled back my Arduino ESP32 board support package (BSP) version from 3.3.3 to 1.0.4
The rest of the configuration is the same (Windows 11, Arduino IDE 2.3.6, Wemos D1 R32 board).
There is no more problem: the COM port opens well and the transmission is perfect.
Hence it's not a exactly Windows 11 problem but a compatibility issue between ESP32 with its latest BSP version and Windows 11.

It would be great if espressif could take a look on this issue.