Often I blog things so that I can stop searching for them. I run across this error all the time…and then have to search for the KB with the fix.
When opening IIS Manager you click on the Web Sites folder and receive the following error: The path specified cannot be used at this time.
The only temporary solution I have found is to perform an IISRESET which is a drag, because the site is usually working fine. The patch information is here: http://support.microsoft.com/kb/946517