Marcel Milić We will be pleased to help you with this problem so have logged a support case on your behalf. We do prioritise customers who have a support contract so please keep in mind it could take up to 48 hours, especially over a weekend, but rest assured we will contact you as soon as we can. You will be contacted at the email address used for this Community. Support Case Id : CS0005861.

Hello,
I got the answer and the link to the possible solution.
I followed the instructions and renamed three directories (folders), but the problem remains.

Hi,
I remembered having problems with a plug-in that I mistakenly installed twice.
I uninstalled it, and Trados started to work fine.
After the upgrade, this problem has popped up again, though I haven't touched any plug-in.
I don't know how this happened, and how the already uninstalled plug-in showed again as active.
I would appreciate it if you had an answer to that so I can use it for future reference.
Thanks!

Hi Marcel, I've sent you a reply from the case opened with our  Technical Support team, and we should arrange for a remote session. 

Thank you. 

Hi Marcel, I am glad that you confirmed (on the case opened with Technical Support)  that the issue has been resolved. For future reference, here an article on how to check and  remove an old or incompatible plugin  from your Trados Studio version: gateway.rws.com/csm