Defrag Tools: #67 - Windows 8.1 - Background Task Hang

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In this episode of Defrag Tools, Andrew Richards and Chad Beeder walk you through a common issues in Background Task applications. We use a Windows Store 8.1 app sample to show how missing code affects the process, and how the process can be reported as having an Application Hang due to non-responsiveness.

Improving apps with Quality reports
Windows 8.1 Application Samples
Introduction to Background Tasks Whitepaper
Defrag Tools SkyDrive (inc. Scripts and ProcDumpExt)

[00:00] - Background Hangs in Windows Store apps
[00:54] - Quality reports - APPLICATION_HANG_...
[04:57] - Dump File - ".exr -1" - Exception Code 0xdfffffff
[06:50]Background task sample
[11:24] - Missing IBackgroundTaskInstance::Canceled handler
[18:08] - Missing BackgroundTaskDeferral::Complete call
[19:39] - Email us your issues at

--- EDIT ----

I looked in to Background Tasks more after taping:

  • BackgroundTaskDeferral::Complete is required in all languages, not just C# as said.
  • In JavaScript, a missing close() call on the web page causes the empty wwahost.exe, not a missing Complete call on the deferral (as I thought).

If you have a hang you don't understand, email the CAB file to and we'll help you.



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