For a project, an internal customer wanted to utilize web services for file reading and writing. Both the file write and read services were utilizing a System.IO.FileStream object, invoking the object's Read and Write methods. Since the location that the web services would be reading and writing from is a network share, two domain accounts were setup and given read, and you guessed it, write permissions each respectively to the share.
The “gotcha” that we encountered was that the accounts that the web services were utilizing needed modify permissions on the server <WindowsFolder>/temp folder in order to generate serialization proxies.
Click here to see what was done to remedy the issue.