Win 10 COM port issue

I like to hear from anyone else having this issue. After a PC boot typically I'm using the IDE to work on some Marlin code for my 3D printer. I upload the compiled code via the IDE. All goes well. I then need to run the 3D printer control software to test my changes. Many time when I try to start the control sw I get an Access Denied error when it tries to open the COM port. If I pull the USB cable and try another USB port it generally works. Then when I try to go back to the IDE and re-upload it gets the Access Denied. And around we go but sometimes it works without error.

Now this did not happen before the latest fall update (1809) to windows. I've been using this work flow for several years with no issue until this update.

Anyone else having COM port issues like this or am I having some local problem? BTW this happens on two different PC and Arduino. One setup is a real Mega and the other is a TriGorilla 2560/ RAMPS clone.

Thanks for any input.

First would be to check device manager for all boards WITHOUT anything else connected to the board. (rule out external board hardware)

Second thing to do would be avoid USB 3.0 ports as they are a known cause of some issues.

Third would be to ensure that the IDE is in your exclusions/white list for any additional security you may have (antivirus and such, try turning off to check)

Fourth would be to watch out for any Bluetooth or other modem type software that may hog a serial port. (try turning off to check)

Fifth would be try all the above on another computer with new KNOWN working cables.

As it seems semi random it might be difficult to isolate.