What Ive noticed since Ive fixed this issue on my pc is that once you set the flashdrive as a readyboost cache stick, you SHOULD NOT remove it or change its physical USB location without disabling it first (right click) (properties)(readyboost) (do not use
this device).
My guess is that its basically seen as a harddrive and cache files are mapped to it, so when you move the flashdrive to another location its like moving a harddrive platter to another location, it cannot find the files in its previous location, hence "readyboost
cannot find the file specified"
Just dedicate a flashdrive to readyboost and leave it alone, its not worth the constant errors to use the jumpdrive for other purposes. 4GB drive is about 5 or 6 bucks, and use current model drives, the old stuff is not fast enough...
I get about 12 - 15 MB/s on USB2 and about 75 MB/s on USB3
If you need the performance boost, its well worth using the USB3!
David