While deploying my custom asp.net application I found it hard to browse through few asp.net pages. I tried to enable directory browsing feature to locate pages. Selecting enabled after clicking on directory browsing gaves me following error
Error: Cannot write configuration file due to insufficient permissions
Looking at above issue I thought that may be I need to start my IIS as an administrator so I closed my IIS and start IIS console again as an administrator but above error remain as is.
I decided to go for some research over the internet and found an unbelievable solution. i.e. My web.conf file was readonly :D.