Virtualbox 'breaks down' with transparent windows contents

[Vadi2]

Using Version 5.1.14 r112924 (Qt5.5.1) on Ubuntu 16.04 64bit, Virtualbox window concents become invisible and thus unusuable:

Graphics are Intel® HD Graphics 520 (Skylake GT2). How can I fix this?

[Vadi2]

[mpack]

Please provide a VM log file. With the VM fully shut down, right click it in GUI. Select "Show Log" and save "VBox.log" (ONLY) to a zip file. Attach the zip here.

[Vadi2]

I've found out that this issue happens when I toggle from fullscreen mode into widowed mode, and I can work around it by toggling fullscreen/widowed mode again. Will see about getting a log.

[Vadi2]

Here is the log.

[mpack]

As far as I can tell, you have not installed the Guest Additions, therefore many graphical features will fail.

See User Manual: Chapter 4 - Guest Additions.

[Vadi2]

I've installed beta 5.1.15 guest additions downloaded from the website, because the ones that come from the application were not loading - my Win10 does not have a CD drive, and I could not find any other way to find the right version of guest additions on my host system or anywhere else. That said, the guest additions are loaded by the guest system as I get an icon - perhaps the two aren't communicating due to version differences. How can I install the right ones when the "Install virtualbox guest additions" option does nothing?

[mpack]

A separate download of the Guest Additions is not required. They are bundled in the main install.

Did you look at that user manual chapter at all? The expansion pack is NOT the guest additions.

If your Windows 10 guest does not have a virtual CD drive then add one.