Xbox bricked after failed update...

Its sad when you cant even update your own controller out of fear of a meltdown and sadly enough these things cost 60 bucks which is pretty expensive in my book

i work for goodwill and we still get lots of xboxes that still(!) work. i'm impressed...my piece of *** xbox 360 elite failed on me after a year of owning it and my slim got bricked by the may 21st 2011 update

My first step in troubleshooting would be to remove the batteries and disconnect from USB, and let it sit for about 10-15 minutes. Then put the batteries back and try again, see if it'll sync up.

I would also see if it'll connect to another device, either computer or mobile device via USB, if you have that available, to verify if it's an issue with it connecting or an issue between the controller and device you're connecting it to specifically.

For clarification, were you trying to update via Windows 10 with the Xbox Accessories App or on Xbox One?

I have had the exact same issue with my 2014 controller, however it turned off after the update and now will not turn on, similar to deano89's problem, I will be in touch if I find a resolution however my best advice is to contact Microsoft support team
and push for a free replacement if your controller is still under warranty, if not push anyway as this is at no fault of your own and Microsoft have us by the balls here

just got the same problem but with the original controller, but the difference is that mine turned off as soon as I hit update and now wont power on whatsoever. So I guess I'm screwed.