drag and drop beats into project?

this might be a really dumb question but when i was working on a project yesterday i dropped a beat into one my tracks and it worked fine. today it’s not letting me drag and drop beats onto a track. can anyone give me some advice on this? thanks in advance.

The track i locked ?
You started Cubase with Admin rights (on windows) ?

The track is not i locked and I am using admin rights.

Bingo, don’t use admin rights