My Galaxy S6 indicates it's downloading and not to turn it off. Anyone else experiencing this?

[AC Question]

I can't turn the device off. I also can't receive or make any calls. Again, anyone else experiencing this?

 

[B. Diddy]

Welcome to Android Central! That's Download (aka Odin) Mode. You usually get to it by pressing Power, Home, and Vol Down when powering on. Is it appearing even though you're powering on normally?

You can force a shutdown by pressing and holding Power and Vol Down for about 10-15 seconds. Then power on normally. Does it happen again?