I had a simular problem on my old phone that was only 8 gb. It showed that I had enough space for it and couldn't download as well. I can't give you the geek explanation but I know how I fixed it. What I did was downloaded an app called link2sd. What it does is it allows you to install and move apps to your external SD card. If your device doesn't have one then unfortunately there's nothing that I know of to fix it. If you do you have to format and rename your SD card exactly how they want it in the instructions. It's been a while so I don't know off the top of my head but I know if you do so it'll solve you problem if your device is simular to mine before. For some reason it holds a certain amount of memory to the side or something. Anyways hope this helps. I'm no pro just some Joe shmoe trying to help out so please no negative comments. Thx