Bringing this back from the dead....
Cortana was not reminding me when I asked it to. This happened to be on my phone, not desk/laptop, but a search brought me to this thread. Anyway, I checked my notifications, and sure enough I had turned cortana off. So I turned it back on.
I started going through the settings, and plugged in my headset to listen (at work) to various chimes for the notification. On W10M, apparently it starts a default music app when you plug in headphones now. No big deal, I canceled out of it, listened to and set my chime and went to cortana to test.
'Cortana, remind me in five minutes to check reminders.' The reminder comes up, and I click OK.
JAMMIN' GUITAR RIFFF!!!!!! (If you must know, the guitar intro to, "She's Only Seventeen" by Winger
youtube.com/watch?v=GlN3oEjMpUQ)
:grin:
Apparently it 'resumed' the music app, even though I had closed it. I think Cortana was happy and needed to jam! :evil:
Anyway, to CONTRIBUTE to this thread, one would think that Cortana could tell you when something built around notifications won't work because notifications are turned off.... Otherwise a reminder is just a to-do list.