Veeam O365: Unable to read beyond the end of the stream

Unable To Read Beyond The End Of The StreamI’ve been using Veeam Backup for Office 365 since somewhere around November 2016. Being part of the Vanguard program, I was afforded an early glimpse at it. I quickly found that I was getting some great use from having it though. Although generally smooth, I do occasionally run into issues.

Most recently, I ran into an interesting error message while exporting a mailbox: Unable to read beyond the end of the stream. Definitely not an intuitive message, however it does sound like some sort of read issue. Being the type of person that I am, I immediately took a look to see if I could fix things myself before evoking support.

NARROWING DOWN THE PROBLEM

The first thing I did was check my log files for Veeam Backup for Office 365. By default, you can find these in c:\programData\Veeam\Backup365\logs. I looked through here for quite a while but couldn’t find anything. I tried following entries by using TextPad and reloading the file every time there was a write, but no luck. It then occurred to me why I wasn’t seeing anything. When restoring data from the backup, Veeam Explorer of Microsoft Exchange is used.

Veeam Office 365 Log FileOnce that light bulb went off, I looked at the Explorer for Exchange log files. These files are located in C:\ProgramData\Veeam\Backup\ExchangeExplorer\Logs by default. This time I was able to find the error message in the log file. At this point, I opened up a support case and sent along the log files, but I kept digging some more.

I noted that there was a reference to Deleted Items right before the error. This led me to believe that the error was related to an item in the Deleted Items folder. I did some testing by exporting the Delete Items folder, which threw the error after a few minutes. I then tried a few other random folders, and all was fine. This pretty much confirmed my suspicion that the problem was with an item in that folder.

FIXING THE ISSUE

I was happy that I opened the case because as it turns out, the fix requires updating some of the DLLs required for the program. I don’t have the technical details, but it would appear that either the items are fixed or ignored in the new version. Without knowing which item was causing the trouble, I can’t confirm which method is used.

Also part of the fix is that you need to run a full backup to a new repository. In my case, I setup a new share and pointed to that location for the repository. The old repository is still accessible with Veeam Explorer for Microsoft Exchange, so I can get at the data if need be.

I thought I would share this information as it was not immediately apparent to me on how to solve the problem. If you need to perform a restore, but keep receiving this error, check your log files. You might be able to figure out where the problem is, and avoid the specific folder.

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