Help MM system download update error

[ScoobyWRX]

Help needed please guys
I rooted about 2 months ago but left everything as stock, everything running smoothly. When the M ota update came through I was expecting to update normally with no problems? Unfortunately it wouldn't install after going through the reboot stage, android man on his back with red exclamation triangle and 'error' underneath him. So decided to unroot, everything seems to be back to as it was originally, bootloader locked, can't install SU apps?
Any ideas what I should be looking for?
Paul

 

[exninja]

Did you try the ota again after unrooting?

Worst case, just go grab the factory image and flash it. Reroot and profit.

 

[ScoobyWRX]

Yes, still the same. Was never too confident with the rooting route to be honest.
Thanks for the reply

 

[ScoobyWRX]

Managed to sort it out using the Nexus Root Toolkit, which was surprisingly easy to use