[TIP] - Ok Google hotword not working - check Accessibility Services
My Moto G updated to the newest version of Google Search yesterday (18.104.22.1689776.arm), which should have enabled the 'OK Google' hotword feature for UK English.....but it didn't work. A bit of head scratching later and the culprit discovered was an app that uses an Accessibility Service to listen for notifications. Disabled that Accessibility Service and hey presto I can 'OK Google, Beam me up Scotty, Do a Barrel Roll' etc etc to my hearts content....
Always worth letting the App developer for the App that uses this Accessibility hack know if this is a problem - it's also easily fixed their end.