ASP.NET Error: Failed to access IIS metabase

The solution is still simple, execute this in command line:

aspnet_regiis -ga <user_name>

The aspnet_regiis.exe is under Windows/Microsoft.NET/v2.0.50727, and <user_name> should be replaced with your account to run the ASP.NET website. You can check it in your website properties dialog in IIS.

If it still doesn't work, you can try to do this as last step:

aspnet_regiis -i -enable

And then execute this to restart related services (usually W3SVC and IISADMIN):

net stop iisadmin
net start w3svc