I cannot access any of my projects in Trados Studio 2019 SR2

I run Trados Studio 2019 SR2 that I migrated to a new computer.

I have run without major problems for about two months, but now, even after reinstalling Studio, I cannot open the existing projects.

When I go to the Files view, it says "Failed to deactivate view Projects".

When I try to open the project again, it says "This file has already been opened in SDL Trados Studio 2019 and added to the project list" but the project list is empty.

I get all sorts of other error messages like "Tab must be part of the Tabs collection" or "Object not set to an instance of an object"

I have loads of projects waiting, so this is of the highest urgency!!!

Ronald

PS I have been a very happy user of Trados Studio since 2011...