# Backups fail with error: Object reference not set to an instance of an object

**URL:** https://forum.duplicati.com/t/backups-fail-with-error-object-reference-not-set-to-an-instance-of-an-object/5570
**Category:** Support
**Created:** [December 9, 2018, 2:37pm UTC](https://forum.duplicati.com/t/backups-fail-with-error-object-reference-not-set-to-an-instance-of-an-object/5570 "2018-12-09T14:37:03Z")
**Posts on this page:** 1
**Showing post:** 26

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### Author: ![ts678](https://forum.duplicati.com/letter_avatar_proxy/v4/letter/t/8491ac/32.png) [@ts678](https://forum.duplicati.com/u/ts678)
#### Post date: [December 27, 2018, 6:38pm UTC](https://forum.duplicati.com/t/backups-fail-with-error-object-reference-not-set-to-an-instance-of-an-object/5570/26 "2018-12-27T18:38:06Z")

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> [@ts678](#):
>
> Actually, the surprising thing about what you posted is that this isn’t the original error. Did that also happen?

> [@ts678](#):
>
> does this have any relationship to the original problem?

> [@jake](#):
>
> But I’m still stuck with my existing backup. Any thoughts on recovery, or should I just scrap it and start over?

What problem are we chasing now? The “Object reference not set to an instance of an object” is so generic an error message that it means little in Duplicati terms without a solid understanding of the code area, and a reproducible test to look at. I lack the former (any readers know Duplicati/Server/WebServer/RESTMethods/CommandLine.cs and its WriteLine?). I set up a debugger, but was not even using that code on my backup.

If that problem has somehow vanished, the “Unexpected difference in fileset”, though of unclear origin, has a simple workaround to try, of deleting the troubled fileset (version of the backup) shown in the error message. [Here](https://forum.duplicati.com/t/unexpected-difference-in-fileset-errors-2-0-3-9/4286/24) is a recent report of success, however if the original “Object reference” still happens, I can’t help further without additional assistance from the community, or you being able to discover a way that I can reproduce it. Seeing a simple test succeed is encouraging, but the key is figuring out the difference between it and failure.

For additional information on how to use the [delete](https://duplicati.readthedocs.io/en/latest/04-using-duplicati-from-the-command-line/#the-delete-command) command for the “Unexpected difference” error, see [this](https://forum.duplicati.com/t/last-backup-was-in-the-future-how-to-ignore-the-last-backup/5782/2), and please feel free to clarify the relationship between these two problems and which is the current problem.

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