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Backup failing after I/O error

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Posts: 1
Comments: 0

Hey everyone, hoping someone can help with this as I can't seem to find a resolution anywhere.

When running my backup task it hangs around 80% for days. The last entry in the log is:


Error occurred while reading the file.
Additional info: 
Error code: 1
Module: 4
LineInfo: 3d9ea26f1bfdefae
Message: Error occurred while reading the file.
Error code: 65521
Module: 0
LineInfo: bd28fdbd64edb8d0
Fields: code : 5
Message: Input/output error

It appears this error occurs during the 'Pending operation 3 started: 'Validate Backup Archive'.' stage.

I've ran chkdsk on the external hard drive but no errors were found.


Any help would be greatly appreciated. 

- David

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Forum Moderator
Posts: 109
Comments: 3973

Hello David,

I'd start troubleshooting with the following steps:

1. First of all, please check if the latest build version of Acronis Backup for VMware is installed. You can download the installation file from your personal account at


2.  Next I would temporary disable Validation after backup and start a validation task manually. This will help to understand, whether the issue occurs only when validating the archive right after backup or independent. 

3. Create a new backup to some other location and test validation. Does it work? 

Thank you,