Failed to call RPC function 'LoadMedium': The remote procedure call was cancelled

Hi ​@skosztur ,

it seems the error described on this KB, the only difference is the LTO version.

https://www.veeam.com/kb4396

Have you already tried the suggested solution?

Anyway, you can continue to work with Veeam support and investigate the issue.

The error typically indicates a communication issue between the Veeam Backup Server and the Tape Server (or the tape library driver subsystem), especially during the medium load operation.

One important step is to check the Device Manager on the server to confirm whether both the LTO drive and the Medium Changer are recognized correctly. Ideally, they should appear as follows:

• LTO Drive: It should be listed with the manufacturer’s driver (e.g., HP, IBM), not a generic Microsoft driver.

• Medium Changer: It's acceptable (and often recommended by Veeam) for it to appear as "Unknown Medium Changer", as this avoids potential conflicts with backup software.

Another useful test is to move a tape manually using the library’s interface. Try moving a tape from a slot to a drive directly. This helps identify whether there’s a hardware/robot issue independent of Veeam.

https://www.veeam.com/kb4396 - is for LTO9. There are no such option for LTO7.

Another useful test is to move a tape manually using the library’s interface - When the error you can do nothing with the library neither but no error is displayd on it. The changer and tape drive is listed as it should be.

The backup run 2 years ok without any issue and now it runs successfuly every 3rd run.

Automatic cleaning enabled

So from my perspective maybe it is caused by some windows update as nothing else was changed on the server. I will se when I patch Veeam to the latest if it does help. 

Wait on the patch and see if that helps. Other than that I would continue with support to get this addressed.

Was there some maintenance for the library and/or the drives before the error occrured?

I had a similar problem one time when the technician did not set the WWNs of the drives properly and Veeam gave the command to load a tape into a specific drive and the library used another drive.

Did you check that the correct drive is loaded with the tape?

The issue sarted to happen when we turned on tape encryption in Veeam on media pool. So I turned it off but the issue persists so maybe that changed something. And not sure why Veeam started to use HW encryption if the library needs a kit and license for it. I thought Veeam will use software encryption.