Powershell batch job fails when run as a scheduled task.

My NAS is a Synology DS223. Largest file is probably a few MB. Total when compressed is currently around 1.8 GB

The Synology DS223 supports both Btrfs and ext4 for its internal storage volumes. During normal DSM setup, Btrfs is the recommended and typically selected file system, but it is not an immutable factory default; the file system is chosen when the volume is created

Unless you changed it to mount an old FAT32 file system it supports much higher file sizes.


Windows is accessing the NAS through SMB, not directly mounting the underlying Btrfs or ext4 file system.

That means:

• Windows does not need Btrfs or ext4 support.
• The NAS handles its internal file system.
• Windows sees the shared folder as a network file share.
• The NAS volume’s limits still apply, including the approximately 16 TiB maximum individual file size.
• FAT32’s 4 GB limit is irrelevant unless the destination is actually an external FAT32-formatted USB drive attached to the NAS.

Therefore, copying a large file from Windows to:
\\NAS\Backups

should allow files larger than 4 GB, 100 GB, or 1 TB, provided:

1. The Synology shared folder resides on Btrfs or ext4.
2. The NAS has enough free space.
3. The application performing the copy supports the file size.
4. SMB2 or SMB3 is being used, which is normal on current Windows and DSM systems.

Do you know for certain how the drive was setup? @jpullam

I appreciate the effort you are putting in to help me, but I think I am going in a good direction now.

To answer your question I built the NAS about 3 months ago and I'm petty sure that I went with the defaults. I have lots of space on the two 4TB droves I installed.

I have been working with 7-zip for a few hours and I now have what seems to be a good functioning bat file. It is as follows:

@echo off
set "SZ=C:\Program Files\7-Zip\7z.exe"
set "DEST_DIR=\\NAS3\Backups\MyDocsArchives"
set "SRC_DIR=\\NAS3\Backups\MyDocsCopy\*"
set "DATE_STAMP=%date%
REM Compress the folder using the date in the filename
"%SZ%" a "%DEST_DIR%\MyDocsArchive_%DATE_STAMP%.7z" "%SRC_DIR%\*"

This creates the back up I want and I think all that is left is for me to set it up in the scheduler.

jpullam said:

The following is my code

Click to expand...

The root cause of the issue is the use of the mapped drive letter N:\. When the Task Scheduler runs the script in the background at night, the N:\ drive does not exist for that session. Windows only mounts mapped network drives for an active, logged-in user session.
As a result, the Compress-Archive cmdlet fails immediately because it cannot find the path, and the Task Scheduler simply logs a very fast process creation (Event ID 129) and exits.
## The Solution: Use UNC Paths
To fix this, you need to replace the drive letter N:\ with the direct network UNC path to your Synology NAS.
An example of a corrected and optimized version of the script
## Critical Task Scheduler Settings
To make sure this script runs properly on Windows 11 while you are asleep, verify these settings in the Task Scheduler task properties:
* General Tab:
* Select "Run whether user is logged on or not". This ensures the task runs at night.
* Check "Run with highest privileges" (Administrator mode).
* Make sure the user account assigned to run the task is the same Windows account you use to access the Synology NAS.
* Actions Tab:
* Program/script: powershell.exe
* Add arguments: -NoProfile -ExecutionPolicy Bypass -File "C:\PathToYourScript\backup.ps1"
* The -Force Parameter: I added -Force to the Compress-Archive command. If the script accidentally triggers twice on the same day, it will overwrite the existing file instead of crashing with a "File already exists" error.

If the task still ends too quickly after these changes, let me know if Windows remembers your Synology credentials automatically (via Windows Credential Manager) or if you have to type a username and password whenever you access the NAS network folder manually.

Take a look at the following script @jpullam

Modify to your needs or keep what you have. Just sharing ideas that work for me.