This typically means something in the installation or upgrade got corrupted. The following is the method to fix the problem, written by user Testbot21, who gets all the credit for first finding the bug as well as the fix for it:
Hello to the Enahnceviews community,
I recently had a problem with running the Chrome Auto-Watcher v1.8 Extension. By this I mean, EnhanceViews was unable to recognize the extension was installed when it was. I could also not click Start-Autowatcher, Start Power-Watcher or Stop via the Chrome Auto-Watcher Extension Icon as nothing would happen. The buttons were broken and all it was telling me was to install it again, even though I had it installed.
There are many things I tried which all failed.
Disclaimer: This is a Chrome Bug in where your extensions get corrupted and need repairing. EnhanceViews admins can not fix this issue and it is most likely not caused by them but a function in Chrome malfunctioning.
So without further ado, here is a step by step tutorial on how to fix the Chrome Extension on any version of Google Chrome if it stops working/functioning altogether.
1. Close Chrome and opening Windows Explorer.
2. Go to the following directory: <drive>\users\<username>\appdata\local\google\chro me\user data\Default\
3. Use Window Explorer search, searching for your extensions id: llgnkbjfcnjfgkgciddcohamdeendcoo (Extension id should be the same for everyone, but each ID is different for different extensions. To find the extension ID go to Settings --> Tools --> Extensions --> Developer Mode.)
4. Delete everything related to the enahnceviews extension
5. Re-open Chrome
6. Re-installing the extension (It will install clean versions of the files you deleted)
7. Enjoy your fully functional extension
*Note: This may fix other issues with the extension as well but I can't guarantee anything*
I hope this tutorial will help anyone having issues with not being able to run the EnhanceViews Auto-Watcher plugin. at al.