As I blogged about previously here there was a file system race condition in the MS App-V client when used on multiprocessor or even hyperthreading systems. I reported the issue to Microsoft after encountering it at a client site and proving it was related to multiprocessor systems. At that time, I had mentioned that Microsoft supplied me with a private fix and that they were working on including that fix into Hotfix Rollup Pack 6. Well that HRP went public today. Definitely a must have for App-V environments. Get the full info on what’s fixed in HRP6 along with a download link off the App-V Team Blog entry here.