Here is a look at troubleshooting the problem if you find that you cannot update iPhone apps.
Keeping Apps Up to Date
iPhone apps are not always the final piece of software, and instead are often open to updates from the developer. These iPhone app updates are key to bringing in new features and keeping the content recent, even shifting the basic format of the app in response to customer feedback. You will find that in your iPhone many of your more well traveled apps will need updates fairly consistently, and this requires connecting to the iTunes App Store to initiate the update. Connectivity issues between the iPhone and its software hub can happen for a whole host of reasons, and if you cannot update apps due to an iPhone error there are going to be a few reasons why this may be happening.
Syncing Downloaded App Updates
The process by which you update your iPhone apps is built right into your iTunes set up from the start. You will first select the Apps section in the left hand panel where you can choose library types. At the bottom right hand corner of this display will be an option that says Check for Updates. The check will begin and you will then be told how many updates there are, which you can then begin. Once these updates have finished downloading you can go back and sync your iPhone again, and the updated apps will sync that way.
If you have already gotten through the search and download stage but are finding that the updated iPhone apps will not actually sync to your iPhone then your issue is not around the iTunes Store connection. Instead, you likely have not set the app sync options to correctly sync to your iPhone. First, you have to make sure that Sync Apps has been selected in the App tab of the iPhone display when it is connected to iTunes. This is often the issue for those who have only downloaded iPhone apps from the App Store on their iPhone and have not done the process through their computer.
If this is already selected then you should go through the list of available iPhone apps that you have downloaded. Make sure that the ones you have downloaded the app update for have a check mark in the box next to them, which will be required for them to be part of the sync. If they are then the process for syncing the iPhone app update should then go through without an error.
Corrupted iPhone Back-up
If you cannot update apps because of an iPhone error the issue is going to be different depending on the error message, but often it will just be shown as an "unknown error." The unknown iPhone error, as well as the Error 0xE800002E message, can often mean that your iPhone back-up files have become corrupted on your computer.
The main way to troubleshoot this is to actually strip the mobile content from your iPhone and computer in an effort to start over. This is going to cause a bit of loss because your back-up will be removed as well, so you should try to identify all your media content that you would like to return to your iPhone afterward. Your iPhone apps will be able to be re-downloaded afterward as well.
First, make sure that your iPhone and computer are in sync in terms of all apps and content. Make sure that you run a sync between the two where all the purchases made on the iPhone are also saved on your computer. When back in iTunes on your computer go to the Applications library and right click one of the apps and choose to go to its source location. Delete every iPhone app that you have in this folder, not just the ones that you have not been able to update. Put your iPhone through the standard restoration process and then go through the process of set up once again. From here you will then need to go back and download all the apps that you originally deleted, which will require you having a comprehensive list of the apps you already had downloaded.
One of the simplest ways to bypass issues with the updating of an iPhone app is to actually re-install that iPhone app directly, which will then install the updated version since that is the current version available at the App Store. To do this you want to first remove the app from your iPhone as it stands. To do this you will press down on the iPhone app on your touchscreen until all the apps begin shaking. A black "X" circle will appear in the upper left hand corner of all the apps, and when you select this on the app you want to remove a window will pop up asking you if you are sure you want to delete the app in question. When you choose to it will disappear from your iPhone desktop.
You are then going to want to actually delete the app from your iTunes account, otherwise it will just re-sync to your iPhone during the next sync process. When in iTunes choose Applications from the left hand panel so that you are given the library screen that lists all of the apps that have been saved on your computer. Find the one that you want to remove, right click it, and choose to delete it. It will prompt you asking if you want to remove it, and when you do choose for it to Move to Trash. This will delete it permanently once you empty the trash on your computer.
Now go ahead and download the app again, syncing it to your computer afterward. The new app that you have on your iPhone will now be the updated version of the previous app. If it is a paid iPhone app then you should still be able to download it for free again since it was already purchased once.
iPhone Error 5002
The iPhone Error 5002 has been a common cause of problems updating iPhone apps, and the process for dealing with this follows a similar line to dealing with a corrupt iPhone back-up. If you are seeing the iPhone Error 5002 when trying to update iPhone apps start by backing up your iPhone apps on a separate disc, and you can usually find them at /Users/myusername/Music/iTunes. Go back into iTunes on your computer and delete all the apps from the Applications library, sending them to the trash when you do.
Once they are all gone go to the back-up location you created and start bringing the apps into iTunes individually. As you do iTunes will indicate if there is a newer version of the app available. This will allow you to bring up each app to its newest update, and once they are all back there go ahead and close out iTunes before restarting it. From here you should be able to sync your iPhone to your iTunes account and receive all of the updated apps, and the error message should not re-occur.
The iPhone Error 5002 message was more common on older versions of iTunes as well, so making sure that you are updated to the latest possible version is going to be another important option.