Hello Gioia Franchi 

Try the following steps: 

1. Close Studio.
2. Go to: C:\ProgramData\Trados\Trados Studio\Studio17\Data
3. Rename the file Studio.lic, e.g. to Studio_old.lic.
4. Go to: C:\ProgramData\SafeNet Sentinel\Sentinel RMS Development Kit
5. Rename System folder to System_old
6. reopen Studio and check if it works in Trial mode. 

Note: If you can't find the path above, open Windows File Explorer, click on View and check "Hidden Items" checkbox.

Thank you,

Sorin

Thank you so much! I tried the all path you mentioned but still it doesn't work and it asks me again the activation code!

Gioia Franchi 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 : 00823659 .