Problem: I'm using ASP.NET 2.0's membership provider for forms authentication. It is working fine in VS environment with the integrated web server. But when I move it to IIS, login control fails to authenticate the same user.
Resolution : In IIS the account(ASPNET or NETWORK SERVICE) access the app_data folder. Therefore the app_data folder must have write/modify permission for this account
I will try to add some troubleshooting tips into this article time to time.