Avamar: WFS and VSS Backup Fails with Duplicate Hash Entry Error

Summary: Customers have multiple Windows servers where case sensitivity is enabled. Avamar Volume Shadow Copy Service (VSS) and File System (FS) plug-in backups may fail with avtar reporting a duplicate entry in the filename cache. This happens when customers enable case sensitivity on Windows servers. ...

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Symptoms

Avamar VSS and FS plug-in backups may fail with avtar reporting a duplicate entry in the filename cache when customers enable case sensitivity on Windows servers. 
2018-08-27 16:21:28 avtar Error <40077>: Found a duplicate entry (f4147bb1a2...) in the filename cache file.

Cause

This is caused when the customer enables case sensitivity on a Windows server. Avamar has developed a software patch to address this issue.

Resolution

To address case sensitivity on any Windows server, follow the options below.

  1. Option 1
    1. Upgrade the Avamar Server to Avamar version 19.10.100.135.
    2. Download hotfix (HF) #338825 from the DELL support site. The following KB article provides instructions for Avamar: Find and Download Hotfix, Patch, Installation, or Upgrade Package from Dell Supportt searching and downloading the hotfix.
    3. Install the HF and then run the backup.
  2. Option 2
    1. Use the below flag on the existing version of Avamar to downgrade the error to a waning to allow backup to complete.
    2. Add the flag to avtart.cmd 
      --dongrade-error-code=40077
    3. For instructions on how to create a .cmd file, see Dell Avamar for Windows Servers 19.10 User Guide page 79, "Generating log files"

Affected Products

Avamar

Products

Avamar
Article Properties
Article Number: 000044200
Article Type: Solution
Last Modified: 18 Dec 2025
Version:  8
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