Windows 8 App Deployment error 0x80073cf6

Today, I have experienced this deployment issue when trying to build and run my Windows 8 app:

[...] 0x80073cf6 See here for more information: http://msdn.microsoft.com/en-us/library/hh973484.aspx

If you search the specifc error ID on the page, you'll see this reason:

The package can't be registered. Check the AppXDeployment-Server event log for more info.

There were indeed error messages in the event viewer. But I still hadn't found the solution.

I found out the solution by accident:

1. Open the task manager
2. Kill "explorer.exe" in the Details tab
3. Restart "explorer.exe" via File->Run new task