error on "install and update" to lollipop 5.1.1 in nexus 6 I have nexus 6 with lollipop 5.0.1. There is setting to install and update to 5.1. I download and install. But facing error on half way. Showing android icon with error text. How should I do that?
I think you are running into the same problem reported over here by fellow Nexus 4/5/7 users on the google product forum page.

Error during updating to 5.0.1

Some of the suggestion found there,


Wipe cache partition
Factory reset. (Warning! This erases all data on your phone)
Unroot your phone if you are rooted.


But none of them seems to completely work will all other Nexus users. But you can give it a try if you are sure about each of the process. As the accepted answer posted by a Google Employee confirms that there is a bug and they are still investigating this issue,


  As several of you have noticed, a new update (still labeled 5.0.1) is
  currently being sent to the Nexus 5 that addresses this issue. If
  you've got a Nexus 5 but haven't received the update yet, please be
  patient as it should be available for your device soon.
  
  Please note that we're still investigating this issue for other
  devices (so far I've seen reports from Nexus 4 and Nexus 7 owners) but
  I don't have further updates or a workaround to suggest at this time.
  We appreciate your patience as we continue to look into this for other
  devices.