So I recently figured out that IIS will use C:\Windows\System32\config\systemprofile as it's "user" directory for folders like AppData in certain situations.
Now, I'm trying to understand why this is and what purpose that directory serves. I've heard that it's used as a "template" for new users, but I'm pretty sure that's what C:\Users\Default User is for. Beyond that, it maybe seems like a "user" directory for the SYSTEM user.. But why would IIS run under SYSTEM?
Can anyone enlighten me as to what this directory does?
21 Answer
Appdata is used for per user configuration and data stores, to achieve a degree of user isolation. The system profile is not a template, it is the profile directory for the system user account, which is the user running the root IIS process host instance (note w3wp processes are run under the identity associated with an app pool not the root IIS process, and are not run from within a service host process).
check out this example using PSEXEC to login as system. just as %appdata% resolves to the logged in users ~\AppData\ directory, so to does it work for the System account:
Windows PowerShell Copyright (C) 2009 Microsoft Corporation. All rights reserved. PS C:\Windows\system32> psexec -s \\localhost cmd PsExec v1.98 - Execute processes remotely Copyright (C) 2001-2010 Mark Russinovich Sysinternals - Microsoft Windows [Version 6.1.7601] Copyright (c) 2009 Microsoft Corporation. All rights reserved. C:\Windows\system32>whoami nt authority\system C:\Windows\system32>cd %appdata% C:\Windows\System32\config\systemprofile\AppData\Roaming>
