SharePoint files returns an error after transferring the files from Network-attached storage

[Tchesco]

Hi all, 

I have migrated some files from a Network-attached storage to SharePoint Online. All files are in the SharePoint now but when trying to open them, there I get error messages of file corrupt.

The picture attached is an example of the error while opening an excel file from the SharePoint.

Please any help. Thank 

[#2]

Hello, what did you use to migrate these files?

[#3]

The migration was done using the Network-attached storage (NAS) migration option

[#4]

Did you use OneDrive sync to sync files to SharePoint online or any migration tool like SPMT or Sharegate?

[#5]

I did not use any of the above, the option to migrate to SharePoint was available in the NAS portal and that is what I used. I did not install or download any other software for this.

[#6 · Accepted solution]

As Bharath says, I would use Microsoft tools to transfer the files, for example have a look at Migration Manager

https://docs.microsoft.com/en-us/sharepointmigration/mm-get-started