WPF application freezes Windows 7

Question

I have a .NET 3.5 WPF application on Windows 7 64bit. I am experiencing odd system freeze issue that happens when dragging and moving the main application window. Basically the entire system freezes (UI) and the application stops rendering. Bringing up the task manager (CTRL+ALT+DEL) unfreezes both system and the application.

The application itself is a trading application that processes a large amount of messages in background threads.

Has anyone experienced this type of issues ? Especially the oddity of task manager unlocking the freeze. What could be the reason for this strange behavior?

I am almost certain it has something to do with dispatching certain actions to the UI thread.

Answer 1

Found some old post on StackOverflow that may help, It is said it may be due to font cache.

"I had the same problem. It was a corrupt font cache!!

See http://social.msdn.microsoft.com/Forums/en-US/wpf/thread/7cc032c1-5f4d-4518-adc6-f53afd051e6b for a solution.

"

WPF Application Hang

Here are the steps that were asked to take.

In Win 7

1. Run services.msc
2. Stop Windows Presentation Foundation Font Cache 3.0.0.0 service
3. Delete FontCache3.0.0.0.dat 

 in XP: 
%systemdrive%\Documents and Settings\LocalService\Local Settings\Application Data 

in Vista: %windir%\ServiceProfiles\LocalService\AppData\Local

4. Restart the machine

What I do know is you can do the following.

The Windows operating system has a font cache file that is located here: C:\Windows\System32\FNTCACHE.DAT

Delete this file, and restart your system.