Hello,
I was using fiddler just fine yesterday. Then I rebooted my system, and tried to reopen it but now every time I try to open it I receive an error dialogue with this message:

Root element is missing.

at System.Xml.XmlTextReaderImpl.ThrowWithoutLineInfo(String res)
at System.Xml.XmlTextReaderImpl.ParseDocumentContent()
at System.Xml.XmlLoader.Load(XmlDocument doc, XmlReader reader, Boolean preserveWhitespace)
at System.Xml.XmlDocument.Load(XmlReader reader)
at System.Xml.XmlDocument.Load(String filename)
at UoFiddler.Options.Load()
at UoFiddler.Options.Startup()
at UoFiddler.Program.Main()

I have tried downloading a fresh copy of fiddler and it shows that same error as well. Does anyone have any idea what might be going on?

bump

I also wanted to note that I had updated my computer with windows update a day or so before this started happening. I'm using windows 7 Home 64bit. I have tried running fiddler in compatibility mode, to no avail.

Since Windows Vista Microsoft has done several things to secure the operating system against malicious software. This creates problems for some programs. That might be the issue with Fiddler here. Where do you have it installed? If it is in C:\Program Files or C:\Program Files (x86) try putting it in a different folder. For those programs that I know have issues with Windows ssecurity I usually place them in one of two special folders I created. I use C:\Programs for software that needs to be installed and for portable programs I use C:\Portable Programs. Also, you might try running it as Administrator and see if that helps.

I feel for you. I just upgraded to Windows 7 and now I can't get Razor to work with my UO client. Oddly though UO Fiddler hasn't given me any trouble. Knock on wood.

Worth a shot to install .net distribution 4 and 2 again

Finally got it fixed! In case anybody else has this problem, here's what we figured out. Since fiddler keeps a folder in \AppData\, that was conflicting somehow. If you're having this same problem, follow these steps:

1. Open command prompt, type echo %appdata%
2. Hit enter, this will tell you where your AppData folder is located.
3. Navigate to that directory, locate the UoFiddler folder
4. Rename that UOFiddler directory to anything you like
5. Run Fiddler

There was something where Fiddler was trying to move some xml files but it couldn't in the old folder. As soon as I opened fiddler after renaming the old directory, it made a new one in AppData and everything works great.

Glad to hear and thanks for posting the fix.