Windows 7 32-bit system. Heavy developer tools installations (VS2008,10, SSMS). IIS 7 has began to act as though it thinks its on a 64-bit install, specifically in terms of the applicationHost.config file. The user was trying to remove sites in IIS7 and it began to start throwing the error below:
Trying various replacements to repair this file were worthless. Viewing the file utilizing Visual Studio or a third party editor such as Notepad++ would show that the file was complete. Just for kicks and knowing of the infamous 64 bit files system replicators, I decided to view the file in windows notepad. Which did show the file was just cut off and EOF for some reason (see below):
It gets better, when you view the file in something like notepad++, it is completed. I even went as far as copying and pasting the rest of the config into windows notepad. It allows me to save it and re-opening it reflects the changes, but as soon as I attempt configuration changes within the IIS7 UI that would reflect in this file, I end up right back at the "not well-formed XML" error dialog in the first image.
This occurred to another developer's machine many months ago. We spent some time troubleshooting it, including removal and re-installation of IIS7 with no luck. The users machine was blown away and rebuilt then but we attributed it to possible OS corruption. Now that this has popped up again, we're concerned it may become a recurring issue. Unfortunately I cannot remember if the previous problematic machine was a 32bit or 64bit machine.