Backup error "Failed to download v6 index after retried 10 times"

November 25, 2025

Product Version

AhsayOBM / AhsayACB : 10.1 and above

Operating System

All platforms

Symptom

After upgrading the backup server from version 6 to 10 or above, the following error message is displayed upon performing a backup of any type:

[MigrateV6Index.downloadV6Index] Failed to download v6 index after retried 10 times

Cause

This issue occurs when the index file of the corresponding backup set is corrupted before the upgrade. The subsequent backup job cannot retrieve the corrupted index file after the upgrade.

Resolution

To resolve the issue, follow the steps below to reset the backup set to v6 and rebuild the index files from scratch.

Stop the AhsayCBS services.
Make a backup of 'users.xml', you can find this in the %Application Home%\conf folder. Save a copy outside the AhsayCBS folder.

Edit the actual 'users.xml' file. Search for the corresponding backupset ID and make sure the parameters are with the same values below:

<Value data=""6.29.0.0"" name=""clientVersion"" type=""string"" />
...
<Value data=""Y"" name=""v6-index-to-migrate"" type=""boolean"" />
<Value data=""NotStarted"" name=""data-migration-status"" type=""string"" />
<Value data=""N"" name=""is-data-migration-mapping-merged-to-index"" type=""boolean"" />

Change the 'clientVersion Value data' to 6.29.0.0.

Save the file.
Start the AhsayCBS services.
Run the single rebuild to re-generate the index files. For instructions on how to do so, please refer to this article: Single User Rebuild (Index Rebuild) for Ahsay Legacy v6 Backup Sets.
Change the temporary directory of the backup set.
Run a backup for the backup set to trigger the index migration.
After the backup job is finished, run a second backup to trigger the data migration.

To check the backup set migration status on the AhsayCBS web console, go to Monitoring > Backup / Restore Logs > Backup Set Log and look at the 'Migrate v6 Status' column.