Hi. It seems that there is no general way of quoting the conditions. in apt_preferences (i.e. the Pin: lines). So having repos like deb-multimedia, which contain spaces in some of their fields, e.g.: Origin: Unofficial Multimedia Packages Label: Unofficial Multimedia Packages Suite: unstable show the problems that could theoretically arise: Package: deb-multimedia-keyring Pin: release o=Unofficial Multimedia Packages,a=testing Pin-Priority: 500 Now it's not really clear, is the origin "Unofficial Multimedia Packages,a=testing" or are there an origin "Unofficial Multimedia Packages" and an archive "testing" specified. Apparently the behaviour right now is, that apt simply looks for commas and splits there, e.g. Pin: release o=Unofficial Multimedia Packages,l=Unofficial Multimedia Packages works (AFAICS) as expected... which of course means again, that the values couldn't contain ",". Cheers, Chris.