brinke@ - Could you please reboot your computer and try to update your Chrome again. If issue still persists follow the below steps.

Download and run the Chrome Cleanup Tool. It’s an app that searches your computer for suspicious programs and offers to remove them for you.
https://www.google.com/chrome/cleanup-tool/

Chrome Cleanup results negative. Canary cannot update and says:  
An error occurred while checking for updates: Update check failed to start (error code 3: 0x800700C1).

Canary looks exactly like the current Stable.  Odd. This is the first time I was able to dl Canary in months. Always got 'unknown error, cannot install.' So when I dl'd this file I right clicked to run as admin, which I am, and it installed right away. Yet it will not update.

It's possible that some files are missing on your computer. To fix, could you please check by uninstalling and reinstall your chrome.

you mean my stable version of Chrome?

Please uninstall your chrome canary and try to install the latest canary M51-51.0.2666.0 from the below link. 
https://www.google.com/chrome/browser/canary.html 

same result;

Version 51.0.2667.0 canary (64-bit)
 
An error occurred while checking for updates: Update check failed to start (error code 3: 0x800700C1).

This is ERROR_BAD_EXE_FORMAT when Chrome tries to fire up Google Update. Ganesh: any idea why this could happen?

This sounds like  issue 442936 : 
https://code.google.com/p/chromium/issues/detail?id=442936

okay thanks, but shouldn't running the omaha recovery component fix this (and all other) errors?