continue to get error System.IO.IOException: The process cannot access the file because it is being used by another process.

I migrated EM client to a new PC and it worked yesterday. Now I get System.IO.IOException: The process cannot access the file because it is being used by another process.
I have put exceptions in the AV program, and have run the DB repair process manually 6 times, and it is clean.  I have searched RESMON for processes locking the accounts.dat file and nothing show up.
What now?