iMac 21.5 Mid 2011 macOS High Sierra V 10.13.6, 4 GB. No new software or hardware changed.
Keys 789uiojklm not working on "one" account. Other two user accounts work fine.
All keys work configured to another Mac. cannot be a keyboard hardware problem but problem on one user account. All keys work on Keyboard Viewer.
Found the problem, spent two hours with Apple Chat support, excellent work worked many areas to second level support took over Chat. Problem which they led me to was I selected a wrong Mouse setting not realizing what it would affect.
Ten (10) keys on one User Id would not work, and the mouse would move left and right.
I was advised by Apple Support to uncheck " Enable Mouse Keys " from the Accessibility menu.
This was at no charge $0, on a 2011 iMac. Great to experience high quality USA chat support from 11pm - 1am to the problem was found. Had a 5 minute response time, for waiting to Chat.
Tried the F6 - fn + F6 and no help . Same bluetooth keyboard configured to MacAir works fine.
Thanks for reply
Try the F6 key (Num Lock).
Some keyboard keys not working
