How do I stop Viber running, without uninstalling the app? When I go Menu→More options→Exit it just comes back. I want it to turn it off completely, so it's not waiting to come on in the background.
No need to root or anything. You can just simply stop it being running by going to Settings>application>viber>force close this will close all the services related to viber. But remind you, you have to force close it every time after you use viber.
Oh there is another way to do that. Start viber, then close it. Then open your multitasking window/history window by pressing the home button. you should see viber there at the bottom. Long press on the screen-shot of viber. You should be prompted with two option, app details/info and clear from list tap on app details/info and click on force close this will do your job.
Hope that helps.
There is an app for this if you have root: Greenify
I have Viber on phone and tablet and it behaves differently. By default, no matter how you stop the service it always turns on when you receive message.
On phone when I go to settings - general - turn off "show Viber status icon", and then I just exit the Viber (via exit or stop service or clean task manager) I am really offline. All messages are received after I turn on Viber myself. I can be offline for days. It behaves like this only when I turn off the Viber icon.
I guess this is a bug but I like it and hope it is not going to be fixed. I don't know if it is bug just for combination of my phone and Android version or if it "works" like this on every phone. On tablet this does not work, Viber cannot be really off.