no more full screen mode

[virshling]

Hello Guys,

I'm new here. Please don't mind me asking a question that might have been answered before:
I can't switch to full screen mode anymore since yesterday, although I didn't make any changes concerning graphics.
All systems had been shut down properly and after next boot, this issue occured.
Host system is Debian buster, guest is Win7. versions of virtualbox, extensions-package and guest extenions match exactly: 6.1_6.1.16-140961
resolution of guest system is limited to 1600:900 while the display is 1920:1080. So, after pressing Ctl+F there is a broad black frame around the vm.
Wether 3-d acceleration is turned on or off, makes no difference, also the amount of memory used for graphics or which graphic card is chosen.
Also I reinstalled the guest extensions.
Does anyone have an idea?
Thanks

bernie



Edit: logfile attached

[virshling]

Solved:

VBoxManage setextradata global GUI/MaxGuestResolution 1920,1080