[LG Optimus L9 P760, P765, P768, P769] xdrc45:
Hi ZanyAL711

You've pretty much done the proper steps to try and get apps to work. The reason that it's not working is that the phone, android version (not supported after 4.0+), most of the downloaded user apps and device system apps, just really doesn't support this feature.

The L9 has only 4gb total memory, which most of that is used by the "/system" partition and leaves a very limited user usable internal memory on the "/data" partition of something only like 1.6gb to 1.8gb of user stirage. Which barely leaves any room for the user to store user apps and or data on the device.

To kind of break it down to you in simple terms...

As i mention above, in android there are 2 main partitions on the devices internal memory:

The "/system" partition - This is where the OS, system apps, etc... are stored. No user data is stored on this partition.

The "/data" partition - This is where all of the user data is stored on the device.

Inside the "/data"partition you have -

"/data/apps"

"/data/data"

"/data/apps" Is where Downloaded user apps are stored and intalled to.

"/data/data" This is where the user "System settings", things that you have changed on the device (ringtones, wallpaper etc) are stored.

Also there are a several other minor partitions on the device but these really have no use to the topic at hand.

Both of these main partitions "/system" and "/data" are on the internal nand flash memory or eMMC (Embedded MultiMedia Card)

The whole data partition is used for user apps and system data only. Which leaves no where for music, movies, photos, documents etc. to be stored on the device.

This is where the external SD card comes into play and allows you to store music, movies, docs etc. off of the devices internal memory. The problem here is that, eben though the L9 has an external/removable SD card, it also has a small internal nand flash memory and it doesn't allow for much user data to be stored in the device and is causing the problem that you have, which is really the phone's lack of internal memory.

So there's not very many more options for you to try other than maybe the following.

You could try the method where you edit the build prop and run a script that allows you to add the feature to move apps to the SD card in "settings/apps/" menu

This can allow you to move some apps to the SD card. Again thought it's not a solution to the problem, but might help.

http://xdaforums.com/showthread.php?t=2372172

Another option and probably the best one... Would be to install kuma82's stock modified ROM/backup. It's not custom ROM... It's slightly modified stock ROM and has extra apps, features and it's themed. Looks great too, way better than the complete stock ROM look. It also has an internal/external memory swapt script. You can read about it in the 2nd post of the ROM thread.

http://xdaforums.com/showthread.php?t=2468880

It's a simple process, doesn't require the bootloader to be unlocked and kuma has directions for what you need and how to install it, in the 2nd post.

I personally have kuma's ROM running on my wife's L9 and no way would I go back to 100% stock ROM after running his.

Anyway hope this helps!