This is a minor UI quirk that's caused by employing multiple overlaying windows inside Excel. The SmartClient isn't actually forzen, it's downloading customizations from your account. If your account contains large number of custom records/custom fields, this may several minutes to complete. The same caching may be triggered while you are on or moving away from the first screen of the Results Template Wizard, Search Wizard or the Add Records Dialog.
Please allow the process to complete without killing Excel using Windows Task Manager.
We will be overhauling some of the UI elements of the SmartClient in version 3.0. This issue will be addressed in that release.