A peer of mine had an odd IIS error that I was able to fix but couldn't explain the cause of the problem. Here is the background.
There is an IIS sever on Server1 which has a bunch of ASP.Net application under the main website. The main website, the one you get when you go to http:\Sever1, used to be its own ASP.Net application that was associated with the directory C:\MainWebsite. The child ASP.Net applications would then be accessed under http:\Sever1/AppName. The main website now redirects to another sever but the directory was left. When the directory C:\MainWebsite was deleted none of the child ASP.Net website would work giving errors about unable to find this or that .Net type. After restarting IIS a bunch of times and trying to add the dlls for the types it was missing I had him create a new empty directory at C:\MainWebsite and restart IIS. Now all the child websites work.
What is the reason this behavior occured and is there some sort of association I have to break or other trick to allow the 'unneeded' directory C:\MainWebsite to be deleted? Cause someone else may try to delete the folder and start the whole cycle again.