We recently had a new management company come in for our business - new AD forest, totally new domains, totally new everything. Our old machines were in their own AD forest and domain. From what I've been told by the Senior IT Manager over there, machines don't migrate well from one domain to another if you don't do a certain step in between removing the machine from the old domain and forest and adding it to the new domain and forest.
I can tell since Flash wasn't playing properly with IE 8; the machines that were migrated over are having strange problems with it, but the machines that were built from scratch for the new domain are fine. We did some troubleshooting to try to fix the Flash installs but we don't see any error messages popping up, and they were even doin the installs with the Domain Admin accounts. After a whole bunch of troubleshooting we are thinking the old domain policies may be blocking the installs from "fully" installing.
From my understanding there's a lot of "throwover/leftover" group policies from the original domain that remain even when you remove the machine from the old domain. I'd like to clear out those old policies so that no conflicts occur when we migrate another set of old stations to the new domain.