You may have faced the error: Unable to lock the ‘admin’ account actions when you want to backup an account sequentially. When you make a backup process, DirectAdmin makes a file named user.action.lock in the user’s data directory. Before every backup, DirectAdmin will check whether the file exists in the directory or not. If the file exists, will be checked for its date/time created. If it was earlier than 30 minutes ago, the backup process will be executed; otherwise, the process throughs an error:
Unable to lock the 'admin' account actions: User's System Quotas set Error locking the User 'admin' actions lock file due to existing lock created on .... Some other process may be doing work on this account.
The fix is to simply delete the file user.action.lock in /usr/local/directadmin/data/users/<user> folder.
rm -f /usr/local/directadmin/data/users/<user>/user.action.lock
Where <user> is the user account you want to backup.
or just wait 30 minutes and try backing-up again.