Scaled and seamless mode of 6.0 are not working properly

[Rabe69]

I just updated Virtualbox 5.2 to 6.0 on my Macbook Air 2014 and now have problems with the scaled and seamless display mode together with my Windows 10 VM.
After updating Virtualbox, I started the Win10 VM and installed the newest guest additions. After rebooting the VM started with a white screen (1. problem), which switches to the login image after clicking on the screen.
The login image with the pin input is not in the middle of the screen (2. problem), the whole seems to be cutoff on the right and on the bottom.
After entering the pin, the upcoming desktop looks distorted (3. problem). Additional the Virtualbox menu "View -> Virtual Screen 1" do not show any entry (4. problem).
When I try to switch to the "Seamless mode" the situation become even more worse: Just a black screen with some chunks of the desktop screen (5. problem).
Only the Fullscreen mode seem to work properly.

[MyCatsNameIsBernie]

Are you using VboxSVGA? There are some problems reported in these forums (although not the specific problem you are having) with 6.0 + VboxSVGA + guest additions. If so, try changing to VboxVGA and see if that helps.

[socratis]

MyCatsNameIsBernie is absolutely right, the new "GPUs" introduced with 6.0.0 have glitches, it's the first release. Try switching to VBoxVGA (the old one).

If that doesn't work, we need to see a complete VBox.log, from a complete VM run, where the problem occurs:

• Start the VM from cold-boot (not from a paused or saved state) / Observe problem / Shutdown the VM (force close it if you have to).
• With the VM completely shut down (not paused or saved), right-click on the VM in the VirtualBox Manager and select "Show Log".
• Save only the first "VBox.log", ZIP it and attach it to your response. See the "Upload attachment" tab below the reply form.