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You have been there: end-users are complaining and your boss demands an explanation why “Citrix is slow” - again. You, the XenApp/XenDesktop admin, desperately look at Task Manager and Perfmon, but you cannot find a thing. Your servers are humming along quite nicely, but still: applications are slow, the system feels sluggish and logons are taking forever. And then, all of a sudden, things are back to normal. What was going on? How do you prevent that from happening again?

This article is part of Helge’s Profile Toolkit, a set of posts explaining the knowledge and tools required to tame Windows user profiles. Roaming user profiles seems like such a good idea at first, but it causes a myriad of problems in practice. One of these problems stems from the fact that the master copy of each profile is stored on a central file share. That file share needs to be accessible over a fast connection from all machines a user is logging on to, or logons tend to become very slow. This proximity requirement is easy to meet if only one site is involved, but what if users roam between different locations, or if terminal servers are distributed across several data centers? Unfortunately, there is no easy answer to this question.