When migrating from SharePoint 2007 to 2010, no matter how hard you try there’s always the chance the the content database upgrade process will throw out errors about features being referenced that are not present in the farm. We have used Stefan Goßner’s WssAnalyzeFeatures and WSSRemoveFeatureFromSite (see his original article) to track down the references and exterminate them. It’s not the fastest thing on two legs though, and I have a fondness for having my SharePoint 2010 tooling in PowerShell because of the flexibility it gives me.
