iPhone 4s 3rd Party Apps not working

On Wednesday I updated my iPhone 4 to iOS5 and all my 3rd party apps worked fine. Then on Friday when my iPhone 4S arrived I transferred everything over. The phone works great and all the core apps work fine, but none of the 3rd party apps work at all. They "blink" if I click on them but none of them will launch - even ones that have just been updated. I have a couple of key apps with years worth of data that I really can't afford to lose. I have done a hard reset. I have restored the software and restored from backup and still the problem is the same.

Any suggestions as to why this is happening and more importantly how I can resolve it?

Thanks.

Solution 1:

Thanks for the suggestions but here is the answer:

The reason this happens is because every time a downloaded app is opened it checks for your itunes password for validation that you are authorized to open that app (as it may contain personal info). From time to time the iphone “forgets” your itunes password. You can fix the missing password by syncing the iphone with itunes or downloading an app from the app store and entering your password that way.

I am up and running with all my 3rd party apps now.

Solution 2:

install another app from the app store... a free one will do. and then once you install that, then all of your apps will start working.. :) hope this helps