IIS Permissions: 'Everyone' works, but IIS DefaultAppPool doesn't?

Question

I got an error stating that the Site.master couldn't be found. Changed permissions on folder to 'Everyone' and problem was fixed. Of course, I don't want to leave it like that so I looked up the correct way to solve the issue and (after removing 'Everyone') added 'IIS AppPool\\DefaultAppPool'.

Now all I get is a spinny icon in the tab for the page. It just spins indefinitely. At least before it gave me a meaningful error, but now it just sits there and never even times out or does anything but spin.

What's the dealio?

Answer 1

Turns out it was an ID10T error. I had the debugger attached and I forgot it was stopped at a break point.