It could probably be a result of SP1, it just might not be.
Vista SP1 Issues:
Support via Technet:
http://forums.microsoft.com/TechNet/...1992&SiteID=17
--
Andre
Blog:
http://adacosta.spaces.live.com
My Vista Quickstart Guide:
http://adacosta.spaces.live.com/blog...3DB!9709.entry
"WarbNull" <> wrote in message
news:4EC30F7D-F8C5-46A9-B9F0-...
> Why is it that Readyboost seem to disappear from my USB drive after I
> reboot
> or restart my computer? If I set it up to were it works then turn the
> computer off it seems to stop working the next time I turn it back on. Is
> this because of the fact that I am now using the SP1 RC for Vista. When I
> didn't have the service pack installed it worked more often but still did
> this every once and awhile. But now that I have it installed it happens
> every
> time.