What's been said is not neccessarily true. If you replace a protected file while it's in use, windows will try to restore it. But if you replace a protected file outside of windows, or in safe mode, it shouldn't try to replace the file on startup. In other words, there is no boot time scan of all protected files to make sure theyre the right version, i expect this to happen in longhorn. Secondly, there is no master list of protected files in xp, although there is a list in windows me. The list of protected files is different on each system and is determined by the catalog files. Just putting a file in the dllcache will probably not make it protected. There is no way to add a file to the protected files, unless you use a catalog. This might be added to longhorn. -gosh