Nano 33 BLE COM port change itself after download

[mcr68]

Hello, this is my first post in the forum.
I've been using Arduino AVR boards for a few years. I just bought a Nano 33 BLE to port my old project from old Nano to the new NanoBLE.
I've the IDE 1.8.19 on three PC and every time after a download any sketch, for example "Simpleaccelerometer" to test Arduino_LSM9DS1 library, the COM number where Nano33BLE is connected changes by itself from COM5 to COM3, COM11 to COM12 and so on with the messagge that the COM port is not more available so I've to set again the comport right from port setting menu.

This happens with three different PC all with Win10. And every time I download a sketch.

[cattledog]

See this previous thread about changing COM ports.

USB COM port keeps changing

I am fairly new to Arduino so there may be a simple answer to this. I am connecting a Nano 33 BLE to a PC via USB for build / upload / debug etc, and it shows up on COM7. However, frequently when I do a compile and upload, at the end of the upload, the COM port switches to COM8 all on its own. The serial monitor then won't work. It is a simple enough matter to change it back to COM7 (the COM port selection recognises that is where the Arduino is), but it is irritating as it keeps happening (n…