Mapped Drives Backup

Hello,
I’ve installed both server and client on the same win server 2012R2 and the setup is as follows:
-Q:\ to W:\ are mapped drives on a FreeNAS
-D:\ is another mapped drive another NAS.
I need to backup the volumes from Q to W on D.
I’m aware of the fact that the system can’t take a snapshot but I’m good with it.
The fact is that even if I have granted the administrator identity to the client service I still get the error about the drives (needless to say that administrator can see these drives).
Here’s a part of the debug just for the first drive.

2018-08-31 17:32:37: ClientService cmd: #IWMRbtOm6l1akJaZeehpI#3START FULL BACKUP group=0&running_jobs=1&sha=528&with_permissions=1&with_scripts=1&with_orig_path=1&with_sequence=1&with_proper_symlinks=1&status_id=13&async=1#token=gvrl5QSP3WnV1soG6lMo
2018-08-31 17:32:37: Async index d5da686479a30dcc7f69c794f2c92af6
2018-08-31 17:32:37: rc=0 hasError=true state=0
2018-08-31 17:32:37: ClientService cmd: #IWMRbtOm6l1akJaZeehpI#WAIT FOR INDEX async_id=d5da686479a30dcc7f69c794f2c92af6#token=gvrl5QSP3WnV1soG6lMo
2018-08-31 17:32:37: Wait for async index d5da686479a30dcc7f69c794f2c92af6
2018-08-31 17:32:37: Removing VSS log data…
2018-08-31 17:32:37: ERROR: Could not open path in os_get_final_path for “Q:”
2018-08-31 17:32:37: Final path: Q:
2018-08-31 17:32:37: Script list at “C:\Program Files\UrBackup\backup_scripts\list.bat” does not exist. Skipping.
2018-08-31 17:32:37: Deleting files… doing full index…
2018-08-31 17:32:37: ClientService cmd: #IWMRbtOm6l1akJaZeehpI#2PING RUNNING pc_done=&status_id=13&speed_bpms=0&total_bytes=-1&done_bytes=0&paused_fb=1#token=gvrl5QSP3WnV1soG6lMo
2018-08-31 17:32:37: ERROR: Could not open path in os_get_final_path for “Q:”
2018-08-31 17:32:37: Final path: Q:
2018-08-31 17:32:37: Removing deleted directories from index…
2018-08-31 17:32:37: ClientService cmd: STATUS DETAIL#pw=idCpOxbnZ9hxiphy47mDkGZ6tO9oxM
2018-08-31 17:32:38: Selected no components to backup
2018-08-31 17:32:38: Creating shadowcopy of “Q” in indexDirs()
2018-08-31 17:32:38: ERROR: Cannot get volume for path “Q:”. Impossibile trovare il file specificato. (code: 2)
2018-08-31 17:32:38: done.
2018-08-31 17:32:38: ERROR: Creating snapshot of “Q” failed.
2018-08-31 17:32:38: Disabling CBT on volume “Q:”
2018-08-31 17:32:38: Indexing “Q”…
2018-08-31 17:32:38: ERROR: Cannot access path to backup: “Q:” Errorcode: 3 - Impossibile trovare il percorso specificato.
2018-08-31 17:32:38: WARNING: Hint: Directory to backup (“Q:”) does not exist. It may have been deleted or renamed. Set the “optional” directory flag if you do not want backups to fail if directories are missing.
2018-08-31 17:32:38: WARNING: Hint: Volume (“Q:”) does not exist. It may currently be not present. If you are trying to backup a network location via mapped network drives please be aware that mapped network drives are per user and the UrBackup client runs as “LOCAL SYSTEM” user per default. See https://www.urbackup.org/faq.html#use_shares on how to backup network locations
2018-08-31 17:32:38: Script “C:\Program Files\UrBackup\postfileindex.bat” does not exist
2018-08-31 17:32:38: Async index d5da686479a30dcc7f69c794f2c92af6 finished with “error - index error”

Any suggestion?
Thanks

See here for the workaround
https://forums.urbackup.org/t/cant-connect-to-mapped-drives-application-permissions-are-set/5913/5