If you receive the message: “Warning: Camera Failed” on your Galaxy S4 it may seem like it is a big issue but it really isn’t and only requires a simple solution. It is more of a software problem than a hardware issue. Try a simple troubleshooting step before going to anything really major. Here's how to fix the Galaxy S4 ''camera failed'' problem.
From the home screen go to menu then settings. From settings go to the application manager then swipe twice to the left to choose the "all" tab. Scroll to the camera and tap it, then tap the force close button, the clear cache button and the clear data button. Note that your preferences and settings may have been deleted when you do this. After you are done with all this, reboot your phone and then check if the camera is working
Failings of the camera may have to do with cached data that has been corrupted. Tapping the force close button will stop the app from running and then clearing the cache and the data will delete the files that are used by the camera when its app is launched and this will also delete any preferences and settings that you have set. This procedure will only affect the camera app.
If the above procedure doesn’t work, then you should try this out if you cannot live without using your phone’s camera. Before you do anything else though, you may want to make a backup of everything important in your phone before you proceed with this.
First you have to tap the menu button from the home screen. The choose settings and go to the accounts tab. Tap reset then tap factory data reset and then select delete all.
This should delete all of the settings and data that can be reached by Android. There are certain folders and partitions that can’t be deleted by doing this. You can delete those using the procedure next.
Wipe Cache Partition
In case the problem is not solved after this try this procedure, turn your phone off. After this, press and hold the volume up, home and power buttons until your phone vibrates. Then let go of the power button but keep on holding the volume up and home buttons until the Android System recovery screen pops up. Press the volume down button to choose the “wipe cache partition” option. Press the power key to select it.
This empties the contents of the cache partition. The files that could not be deleted by doing a factory reset are now deleted. This should solve your problem.
What do you think of these solutions? Did they work for you? Let us know in the comments.