it's a 1000 GB external drive with 100 GB free.
Everything was fine but a had a power interruption a few days ago and the problem begun when started syncing block headers from the start. It gets stuck at the same date everytime I try. It runs smoothly a then stays there for days.
Regarding your problem, can you go to the data directory and delete everything EXCEPT wallet.dat. Please keep a backup of wallet.dat if you have it. Start the client again and it should synchronize fine.