The issue is there's a VDI that's not in the right map. It's hard to tell why without having a deeper look.

Thanks, this works!

Since it was somewhat critical (urgent migration from other pool), I had to switch the pool masters and had to restart the xcp028.

But I downloaded the system log. Maybe you find the cause of the problem there?

BTW, before restarting the host, I was not able to download these logs (failed).