This is my second time experiencing this issue. I have a Samsung Gear S since November 2014. On two occasions the screen has not booted up after a full night of charging. I will note that I have the luxury of just taking out the sim card and using other devices while my smart watch is down. Here is what I have figured out: after traveling for many weeks I arrived home and plugged in my watch into a power strip outlet to charge all night. I have used this power strip before however it gives me issues when I unplug it and plug it back in after traveling. The watch was plugged in all night, when I woke up the screen would not turn on. Complete blackness. The charger is showing a blue light which means it does have some juice in it. I try to start it all day, doesn't work. Yet my Note 4 shows its connected via bluetooth. I plug it into another outlet directly in the wall, plug shows red. I wait 8 hours, still will not boot up. I unplug it and go to sleep. Wake up and try to start it, it works. Boots up fine. Battery shows 1%. Plug it into charger (same outlet as before), wait 20 minutes, the battery is now showing 10%. Now it starts up fine. I have experienced this twice. Both times after 24 hours the watch boots up again. Either there is a strange timer in the flawed code, or a spurt of electricity causes a 24 hour delay in booting up. Very strange. In the mean time, Samsung offered to replace the watch but I don't have time to send it in. Samsung indicated that it could take weeks to return. No loaners.