I'm running NIS version 19.9.0.9 and also NU 15 (which I update frequently). I've been having problems using ReadyBoost (Toshiba Satellite with Vista). The problem is when inserting a Flash Drive stick I can't get the ReadyBoost to work and keep getting 'can't find sfcache,exe to open file'. The laptop was working fine several years ago when I last used ReadyBoost and seems to work fine in all other areas presently except ReadyBoost. Could one of the NIS or NU operations have purged the files such that ReadyBoost needs to be re-established. ReadyBoost still shows up as an item in my files? Any suggestions on steps to take to re-establish? Unfortunately I don't have old backups.