So as soon as I got my Nexus 5, I installed the free version of Nova Launcher. Then, around Christmas time I bought the prime version, and installed it as well, no problems. Then, my phone had a spasm, and I had to restore from backup all of my apps. Now. I am unable to install the prime version. I get an "unknown error during installation. '-24'" message whilst in the notification bar it says "installing". I've tried reinstalling both versions, and I've messaged the help email on their google play store page, but au haven't had a response in a month. So does anyone know now to resolve this problem?