Gnome Shell Restarts

[kenoi]

Since upgrading from Debian 8 and VirtualBox 4.3 to Debian 9 and VirtualBox 5.1, I've been encountering a strange behaviour whenever VirtualBox is launched. Namely, the Gnome 3 Shell (desktop environment) crashes/restarts sometimes multiple times just before VirtualBox shows its windows. I am wondering if this behaviour is intended/programmed, or some sort of clash between Gnome Shell and VirtualBox in the use of the graphics hardware.

I have an AMD Radeon 3 Mullins graphics card running using the open source AMD driver provided in the official Debian repositories (firmware-amd-graphics).

In any case, is there any way to prevent this from happening?

[kenoi]

Nothing related seems to be reported in the log file:

VBoxSVC.log

(3.7 KiB) Downloaded 6 times

Edit: Actually, it looks like I'm using 5.0 now, but 5.1 was behaving exactly the same (hence why I downgraded to 5.0, trying to get rid of this problem).

I've also tried clearing all VirtualBox config and VM files, effectively creating a brand new install first run, to no avail. Same behaviour (clash).