During a fault finding situation I ran into the problem where I wanted to replace the system account for the application pool for a WebApp.
(I got an “Service unavailable” error message when even the settings.aspx on the site was called, if I remember correct.)
I succeeded to create a new web application user manually by doing following:
- In Windows Local Users & Groups: Create a new app pool user. Lets call him sp_proc_myapp1
- Put the new user into the groups WSS_WPG and IIS_WPG
- In SQL manager: Create a new SQL login for the new user and set the default db to wss_content_myapp1
- SQL login user mapping:
- sp_adminContent_xxx: public, WSS_Content_AppPools
- sp_Content: public, WSS_Content_AppPools
- wss_content_xxx: public, db_owner
- Replace the user on the Application pool from the IIS manager
But instead of doing it manually like in the example above you can just use Central Admin to create a new web application and use the user from step 1 above as app pool user. Then Central Admin does the rest for you :-) and you only have to change app pool user in step 5.