Restore error: "Index was outside the bounds of the array"

Support
1

Hello,

I am attempting to run a restore and consistently get the error “Index was outside the bounds of the array.” I am running Duplicati 2.2.0.3 - 2.2.0.3_stable_2026-01-06 in docker on Unraid.

I am trying to restore from an Unraid NAS to a Win 11 machine via an SMG share.

The errors in the log are:

"2026-01-22 12:16:25 -05 - [Error-Duplicati.Library.Main.Operation.Restore.VolumeDownloader-DownloadError]: Error during download\nIndexOutOfRangeException: Index was outside the bounds of the array.""2026-01-22 12:16:25 -05 - [Error-Duplicati.Library.Main.Operation.Restore.BlockManager-BlockCountError]: Block count in SleepableDictionarys block table is not zero: 2\nFirst 10 blocks: 2992075, 3000315""2026-01-22 12:16:25 -05 - [Error-Duplicati.Library.Main.Operation.Restore.BlockManager-VolumeCountError]: Volume count in SleepableDictionarys volume table is not zero: 2\nFirst 10 volumes: 43040, 43134""2026-01-22 12:16:25 -05 - [Error-Duplicati.Library.Main.Controller-FailedOperation]: The operation Restore has failed\nIndexOutOfRangeException: Index was outside the bounds of the array."

I have run a database repair and it did not help.

The restore job restores the files to the target but they are size of 0Bytes.

I have selected earlier version of the backup and it did not help.

Please help.

…Steve

2

I got this exact problem when I was trying to restore to a RAM disk folder (/dev/shm) in Linux. It worked for me restoring to an SSD drive on that machine. See this, for example:

https://forum.duplicati.com/t/restore-failing-on-every-attempt/21786

Can you try it to a folder on the same machine as duplicati, and then copy it over manually?

3

Danny,

I forgot to reply to this. I did try this method to restore to another share on my unRAID NAS and it did not work. My apologies for forgetting to let you know.

…Steve

4

Please don’t worry,

Dan

5

I’m having the same problem. Did you ever figure out the solution?

6

I’m definitely not an expert. I believe the solution is using the –legacy-restore option during restore or using the new beta version or waiting for the new stable version to come out (see The restore fails immediately with the following error: Index was outside the bounds of the array - #11 by kenkendk ). My restore turned messy from my own stupidity.

7

What were your mistakes so I don’t repeat them. :thinking: I did a complete database rebuild but that didn’t work. I’ll try enabling that option now and see how it goes. I’m not seeing the ability to add “advanced options” to a restore job. I see it in the “Options” section but it doesn’t seem to be saving the settings. When I exit and go back to options, the entry is gone. I’m trying in the legacy interface now.

I spoke too soon. seems to have saved in the new interface. Maybe it just needed a refresh. The legacy interface is so painfully slow when selecting files so I’m glad. Here goes nothing…

8

Success! Thanks for pointing me in the right direction.

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