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NinjaOne Backup — Error 342: NAS Write Error

Audience: T2 Use when: Backup fails with "Error 342: NAS Write Error."

What This Error Means

Lockhart connected to the NAS, authenticated successfully, and attempted to write backup data — but the NAS rejected the write or the write failed mid-operation. The local leg of the backup could not complete.

Common Causes

Cause Signal
NAS share permissions changed — dtcbackup lost write access Auth works but writes fail
NAS volume is full Free space near zero
NAS filesystem error NAS admin shows volume degraded
NAS drive failing — write errors at hardware level SMART errors on NAS drives
SMB write permissions set to read-only Share properties show read-only
NAS quota applied to the backup folder/user Quota exceeded for dtcbackup account

Step 1 — Test Write Access to the NAS Share

# Try writing a test file to the backup share (run as SYSTEM via PsExec, or test manually)
$testPath = "\\NAS-HOSTNAME\backups\ninjaone\writetest_$(Get-Date -Format 'yyyyMMdd').tmp"
try {
    [System.IO.File]::WriteAllText($testPath, "write test")
    Write-Host "Write succeeded"
    Remove-Item $testPath
} catch {
    Write-Host "Write failed: $_"
}

If write fails: the problem is permissions or the NAS rejecting writes.

Step 2 — Verify dtcbackup Account Permissions on the NAS

Synology:

  1. DSM → Control Panel → Shared Folder → backups → Edit → Permissions tab
  2. Confirm dtcbackup has Read/Write permission (not Read Only)
  3. If using advanced permissions (file/folder level): also check the ninjaone subfolder specifically

QNAP:

  1. QTS → Shared Folders → backups → Edit → Permissions
  2. Confirm dtcbackup has Read/Write

Step 3 — Check NAS Free Space

Even if Error 344/345 wasn't fired, the NAS volume may have just run out of space between alert checks:

  1. Log into NAS admin → check volume free space
  2. If at or near zero: follow the Error 344 cleanup steps (recycle bin, orphaned folders)

Step 4 — Check NAS Drive Health

Write errors can originate from a failing NAS drive that can still read but fails intermittently on writes:

  1. NAS admin → Storage Manager (Synology) or Storage & Snapshots (QNAP)
  2. Check SMART status for all drives
  3. Look for: Reallocated Sectors, Pending Sectors, Uncorrectable Errors — any non-zero values are concerning

Step 5 — Check for NAS Quotas

Some NAS configurations apply disk quotas per user or per folder:

Synology: Control Panel → Storage → Quota — check if dtcbackup has a quota set QNAP: File Station → Properties on the backup folder — check quota settings

If a quota is set and the backup has grown beyond it: either increase the quota or remove it for the backup account.

After Resolving

  1. Confirm the write test from Step 1 now succeeds
  2. Trigger a manual NinjaOne backup run
  3. Monitor to completion — confirm no Error 342
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