unable to log into guest after installing guest additions 5.0.18

[CMG]

After upgrading to 5.1.8 (host is OSX 10.11.4) and upgrading guest additions on guest (Ubuntu Desktop 14.04 LTS - 64 bit) from 5.0.16 to 5.0.18, I could no longer log in to any of the accounts on the guest machine.

I reverted to snapshot of the VM with the previous guest tools (5.0.16) installed and I was able to log in OK (still using VBox 5.0.18)

[frank]

Works for me and I tried different guest kernels. Which exact version of Ubuntu is your guest? Did you install some/all lts-utopic/lts-vivid/lts-wily packages? Which version has your guest kernel? And could you attach the complete /var/log/Xorg.0.log file? For doing so it should help to switch the guest to a text console (HostKey+F1) and login there.

[michael]

If you are interested in solving this, please provide step-by-step reproduction instructions starting from a fresh virtual machine installation.

[frank]

Please reopen if still relevant with VBox 5.0.22. Make sure to have the Guest Additions updated to 5.0.22 as well.