Have you installed iOS4 on your iPhone 3G or GS? Or, migrated to the new iPhone 4? Did you notice some of your apps stop working or start doing funny things? Maybe apps are launching then returning to the Launcher screen.

When something new comes out, we forget the basics and expect the worse. Nothing wrong with that, history has shown that we should expect major updates to bring a few disappointments in with all the new power and functionality.

First, try restarting the device… holding the ‘Home’ button and the top button at the same time will get you a Red swipe bar to ‘Shut Down’. After everything has shut down, tap the button on the top to start your iPhone back up, it will take less than a minute end-to-end. This will clear up most memory issues where you have an app that has gathered and holding memory another one of your apps want.

There are in fact a few apps on the market that just wont run on iOS4, no matter the hardware. Some need the power of the iPhone4 hardware. These apps have features that the developers where not able to create by following all of the ‘rules’ that Apple suggests, reaching into undocumented features that can at any time stop working when Apple stops bringing them forward in an update. These situations are few and far between, the developer will know if you ready out and ask. Most are working on a fix right now and need to go through the process of making it avail in the iTunes App Store.

More times than not though, something didn’t come through with the app that it needs to run. A few apps that seemed to be lacking some power after the release of the new OS where updated by the developers right away. Just doing the update through the iPhone’s App Store program will take care of a few. If issues continue, concider removing the app and installing fresh/new.

Removing/Reinstalling is fast and easy. Tap and hold on the icon, tap the ‘x’, then tap the ‘Home’ hardware button to return the Launcher to the regular view. Go to the App Store ‘app’, search for the app and choose to install. You will need to put in your account password, but you wont be charged for the app again.

There is some pain that can come from this removal/reinstall… some apps loose their settings or custom searches/history you may have.

Start with the basics before assuming the worse, it makes for a happier day when any of the above quick fixes work and you can return to your day.