System.UnauthorizedAccessException to BlobCache Folder

This is a common scenario that we use blobcache in multiple application hosted under same server, but they are running under different app pool /app pool accounts.

This can even make your server slow or stop responding with access denied message for blob cache folder.

Here are few work arounds you can go for :

1. For each web app , use new root folder in drive.
2. Give WSS_WPG full access on all these folders.
3. Use same app pool account for all web applications using blobcache.

References:

http://technet.microsoft.com/en-us/library/cc263445.aspx

http://support.microsoft.com/kb/2015895