Just try these steps

 

  1. occ ‘files:scan –all’
  2. occ ‘files:cleanup’
  3. if already solved stop where, if not proceed with step 4
  4. occ ‘maintenance:mode –on’
  5. sign in to your mysql db and run: “delete from oc_file_locks where 1;”
  6. occ ‘maintenance:mode –off’