Hello again, Hyper-V version numbers are not compatible with the encoding used in virParseVersionString: https://gitlab.com/libvirt/libvirt/-/blob/master/src/util/virutil.c#L246 For example, the Windows Server 2016 Hyper-V version is 10.0.14393.0, so its “micro” is over 14 times larger than the encoding allows. My current workaround is to truncate it to something that works (E.G. 10.0.143), but that's clearly less than ideal. Is the output of virParseVersionString stored on disk at any point? Would changing its output type from unsigned long to unsigned long long cause any compatibility issues? That would allow “minor” and “micro” to be up to 6 digits each and would be a quick, easy change. Thanks, Matt