Environment.GetFolderPath(Environment.SpecialFolder.InternetCache) returns empty string in ASP.Net project

Question

I am developing ASP.Net project (framework 2.0) on local machine (Windows 7). IIS 7.5 is the local webserver.

When I run the project locally Environment.GetFolderPath(Environment.SpecialFolder.InternetCache) returns empty string.

I am a bit sheepish and frustrated since I encountered this issue when I setup this new dev machine, but cannot remember the solution and cannot find solution by Googling. Others on the dev team running XP do not encounter this problem.

I am expecting a return of C:\Users\DefaultAppPool\AppData\Local\Microsoft\Windows\Temporary Internet Files.

Not sure if this a iis setting issue or can I set the environment variable somewhere.

Thanks, Jeff

Answer 1

I'm 99% sure this is going to come down to a permissions issue. In IIS7, there is a new "user" called AppPoolIdentity that is the default identity for an app pool. This user has much lower permissions than the defaults in IIS 6.

I can reproduce your issue, I have to set my AppPool to run as either LocalSystem or a specific user with administrative rights to retrieve Environment.SpecialFolder.InternetCache which makes sense when I look at the folder in question and view it's permissions.

Be aware, there are security issues with running IIS app pools with higher permissions.