@racom.jiristerba Hello, this appear to be bugs we are already fixing in the build currently in the testing repository. Please see this post for instruction to install the updates : https://xcp-ng.org/forum/post/108803 These two bugs are: the chain being RO sometime which the tapdisk process doing the coalesce can't access and a bug with the LV being in use when it's trying to refresh the VDI it was coalescing and it's parent following the cleanup. Both of those are fixed in sm-3.2.12-25.1.xcpng8.3