Error connecting to undo manager

 vs_errorWhile developing a web application for a friend of mine, I ran into a Visual Studio error message I hadn't seen before: Error connecting to undo manager of source file 'D:\Development\SomeWeb Application\Default.master.designer.cs'.

The error occured whenever I tried to start the (web) application in debug mode. The application did start OK after the error message though. Starting the application without debugging didn't cause the error.
I closed the solution file I had opened, but that didn't solve the  issue. Stopping the ASP.NET Development Server didn't do anything either. I had to exit Visual Studio al together to get this error to go away.

I searched for this specific error, and saw it already occured in Visual Studio 2005 SP1. Scott Hanselman has a blog post on how he solved this issue. Now, in Visual Studio 2008, this error still seems to be in there...

Published Mon, May 5 2008 6:51 AM by Rick van den Bosch
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Comments

# re: Error connecting to undo manager

This error is really pissing me off :(

Tuesday, October 21, 2008 11:58 AM by Jon

# re: Error connecting to undo manager

Hello,

here you can find a very simple solution:

social.msdn.microsoft.com/.../79e84cfe-3d4b-43c7-8d86-723208e4a64c

From that post:

"This happens only occasionally when making changes to the aspx file, and then hitting F5 for 'Start Debugging'.  If I manually modify the the designer.cs file in question (just add a space somewhere), save it, and go, the problem disappears."

I tried it and it works!!

Wednesday, January 07, 2009 5:11 PM by Federico

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