Hi thanks for your response, it help me to find the actual error.
Here is what I ended up to do.
First i moved all folders with image backup for the client kxxx to another location.
Then I started a new full image backup and then got this other error
ERROR Could not read MBR. Error message: Backup GPT magic wrong 1
ERROR Cannot retrieve master boot record (MBR) for the disk from the client.
This i also discused here Could not read MBR.
On the client, where no errors about MBR was logged, I fixed the harddrive MBR.
After that I could not run a image backup, because I still get the first error.
I ended up completly remove the client from UrBackup server, delete the Urbackup software on the client. And then added as a new client with another name. Now it’s running poperly.