Just bought the tab s 10.5 16gb wifi. I have 10-15 apks on my SD card and I install them one by one and after about 8 or 9 the tablet no longer allows me to press the install button. No error messages and I know the apks are good as I have them on my s3 and note 10.1. One time I shut tablet off and back on and it allowed couple more then stopped again and another time I ended all in task manager and one more installed. I did a factory reset and again 8 or so installed then nothing task manager and restart no longer work. Please help love the tablet but can't deal with this issue. Called samsung and they refused to help as they don't support apk installs. Tried explaining that some apps like Amazon app store can't be gotten on play store.