I have an old iMac on MacOS 10.13 High Sierra with the standard Magic Keyboard (before the current MK2). I normally use the iMac in Target Display mode, and then use Screen Sharing from my newer iMac to connect to it when I need to do something directly on the old machine. Naturally, I use the newer keyboard attached to my newer iMac.
A few days ago, I found that most of the keys on the old iMac appear not to be working. After a lot of testing, I can say the following:
- The old keyboard connected to the newer iMac works well
- An alternative Bluetooth keyboard connected to the old iMac also has the same problem
- An alternative Wired keyboard connected to the old iMac also has the same problem
- Everything is fine when I enter using the newer iMac keyboard on screen sharing
- I have ensured that mouse keys and slow keys are turned off
All this suggest that there is a software problem.
I had it working for a while. I then restarted, and it worked for a while longer. Now it’s gone back to the problematic behaviour, and I can only type the
a key, for some reason.