Dear all, Today I have checked it again as you suggested. The results are as follows: 1. When put comments on English (with Latin letters) everything works well. I can start the guest both from virt-manager and from virsh 2. When I put some comments with Cyrillic letters in the field 'Description' I can not start the guest machine and have got the error message as already have reported from the virt-manager, but can start it from virsh, using the command virsh start guest_name. And some strange happens by starting from virsh - a moment after the command virsh start ... get started my text in the field 'Description' disappears from the field and all time when this particular virtual machine is running started by virsh it is not visible there. But when this machine get stopped again it appears there again. 3.When I put some comments with Cyrillic letters in the field 'Headline' I can not start the guest machine and have got the error message as already have reported from the virt-manager. Also in this case I can not start same guest machine by virsh. When I start this machine (the name of it is 'centos7.0') by virsh, I have got following error message on the command prompt: error: Domain startup failed centos7.0 error: Hook script execution failed: internal error: Child process (LC_ALL=C PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin /etc/libvirt/hooks/qemu centos7.0 prepare begin -) unexpected exit status 1: Traceback (most recent call last): File "/etc/libvirt/hooks/qemu", line 281, in <module> tree = etree.fromstring(vmxml) File "src/lxml/etree.pyx", line 3227, in lxml.etree.fromstring File "src/lxml/parser.pxi", line 1871, in lxml.etree._parseMemoryDocument File "src/lxml/parser.pxi", line 1752, in lxml.etree._parseDoc File "src/lxml/parser.pxi", line 1066, in lxml.etree._BaseParser._parseUnicodeDoc File "src/lxml/parser.pxi", line 598, in lxml.etree._ParserContext._handleParseResultDoc File "src/lxml/parser.pxi", line 709, in lxml.etree._handleParseResult File "src/lxml/parser.pxi", line 638, in lxml.etree._raiseParseError File "<string>", line 4 lxml.etree.XMLSyntaxError: Char 0xDCD0 out of allowed range, line 4, column 10 This is the result of my tests now. Strange enough in past even in my Leap 15 based KVM this problem was missing. I believe it show up after some packages update of the host operation system via zypper up. I very much hope you can easily fix this problem in the near future or else we might be forced to install the KVM server with another operating system, because with a large number of machines, these notes are essential to their management. With best regards,