SDL Trados 2017 doesn't open

I currently cannot open SDL Trados 2017. The taskbar shows that the software is currently in use, but I don't have access to the window. I click on it and nothing happens.

This morning I experienced issues opening MultiTerm (Trados was then ok). Now MultiTerm works fine, but Trados doesn't. 

I upgraded Trados 2017 from Trados 2014 2 weeks ago and I installed the Glossary converter this week. Everything has been working fine until today.

Thanks in advance!