If the Web Access site shows a blue page with error "An unexpected Error occoured" after upgrading to vWorkspace 8.5, this is due to an unsaved theme in the Web Site settings.
To recover from this state, open the vWorkspace Management Console and navigate to the Web Access Node. Open the properties of the Web Site and select Browser Interface Settings / Themes on the left Hand side. Now choose either one of the pre-configured themes or save the Unsaved Theme with a new name.
Thanks for the tip 🙂
I can't mark your own post as answered so I'll mark my own but if you want to reply, I'll give you the credit.