Upgraded VBox GAs to 6.0.12 low resolution, no shared folders, copy/paste

[SamH]

Here we go again: I upgraded VirtualBox to new version and on my Ubuntu 18.04 host and guest VirtualBox guest additions fails to upgrade/work once again.

After the upgrade I only have a very low screen resolution on the guest system. Copy and paste between the guest and host not working, shared folders don't work and I can not mount VBox Guest Additions CD any more...

Is there somewhere a description how to revert back to old VBox Guest Additions?

Thanks.

[SamH]

I uninstalled 6.0.12 and installed 6.0.10 on the host. Now I can not mount VBox_GAs_6.0.10 with the following error message: Error mounting system-managed device /dev/sr0: unknown filesystem type 'iso9660'

[SamH]

Finally up and running on 6.0.10 thanks to accepted answer here: https://askubuntu.com/questions/596998/ ... pe-iso9660

[socratis]

Error mounting system-managed device /dev/sr0: unknown filesystem type 'iso9660'

That sounds, and it was after all, a problem with your guest, not VirtualBox.

Marking as [WorksForMe].

[SamH]

No, the main problem is not solved. I tried to upgrade to 6.0.12 and guest additions failed again (look at at least three of my past reports (bugs or forum) where the same story happens when I try to upgrade VirtualBox).

So, tell me, how can I make sure upgrade will not fail and I will not lose one day or more of my life trying to get everything back working again? I am really interested what is it that I am doing wrong or what is it wrong with my system that when I try to upgrade to new version of VBox guest is not working correctly (guest additions not working: only low screen resolution, no copy paste between host and guest, no shared folders, ...)?

Thanks.