Cannot use TMs with Trados Studio 2016

I have been using TMs with Trados Studio 2015 without any problems until today.

Today however, when I try to add a termbase to a translation, I receive the error message:

"There was a problem opening the termbase at D:\…. .

Check that this is a valid termbase and that you have permission to access it."

This now also happens with existing termbases in existing project.

They worked fine yesterday, but nothing works today. What is going on?

 

I remember a similar thing happening with an earlier version of Trados some years ago.

Has SDL Trados changed something again?