Thursday, February 2, 2012

Expression Blend Bug–Can’t Open UserControl

Ever seen this when trying to work in Blend?

(Element Name) is not supported in a windows presentation foundation (WPF) project.

or this?

(UserControl) is not supported in a windows presentation foundation (WPF) project.

Well, I ran into this and had a tough time figuring out what was going on. There are a lot of forum posts out there talking about the topic, but no real solution that I have found. I kept on trying different things and was able to overcome it. Here is what I did to fix it.

I went to the solution explorer in visual studio and right clicked on the project file for the project that was having the problems. I selected ‘Edit Project File’. This unloads the project from the current solution and opens the project file in the xml editor.

Towards the top of the file you should see something like this


After my offending project file with other functioning project files, I noticed that my platform was set to x86 rather than AnyCPU like my other projects. I changed it to AnyCPU, saved, reloaded the project, built the solution and then tried to open the UserControl in Blend. This fixed the problem!

If you are having this same issue, I’d give that a shot. Good luck!


  1. Thank you!! Was driving me crazy!!

  2. Thank you for the post.

  3. When does Microsoft plan on fixing this? This just plain annoying.