Why would the apps on an iPod Touch stop working?

Answer 1

When apps stop working on an iPhone or iPod touch, it is usually due to software corruption. This can occur for several reasons, but for the sake of this answer, we will forego discussing the various causes and focus on resolving the issue.

To remove corrupted applications, follow this two-part solution (read to the end of this answer before doing anything):

1. Remove the corrupted apps from the iPhone or iPod touch. This can be done by restoring the device in iTunes. After restoring the device, make sure to set it up as a new device - do not restore from backup.

2. Remove all apps from the Applications section in iTunes. Chances are, the corrupted apps have backed up to your iTunes library, so when they sync back to the iPhone / iPod touch, they'll start to cause trouble again. Make a note of all the apps you'd like to keep, then delete all apps from iTunes. Re-download them from the App Store (you won't need to pay for them again), and re-sync them to the iPhone / iPod Touch.

Of course, before doing any of this, you'll want to make sure all of your information is synced to the appropriate places on your computer (addresses, calendars, notes, etc.), or backed up somewhere else.