I've met a problem setting up a remote desktop - AnyDesk couldn't connect since remote computer had no monitor. And I've found a workaround - I've setup a virtual monitor with usbmmidd that adds a new monitor with command deviceinstaller64 enableidd 1.
I've created a batch file with this command and added it to shell:startup so it will set it up automatically. But since shell:startup is running multiple times during one session this command keeps creating new virtual monitors (up to 4).
Any ideas how can I make sure that it will add just 1 virtual monitor?