I have experienced the exact same problem using my wireless keyboard as described in the initial posting of the subject. When using the screenlock password the box fills up with a stream of unknown characters and completly renders the keyboard useless. I have to restart the computer to put things tight again and, for a while, the screen lock works fine but then without warning the same problem occurs. I have reverted to a normal keyboard which I used used on my old Apple Computer and to date (the last 8 days) there has not been a problem logging in. My iMac 27" is a late 2013 model bought with wiresless keyboard and mouse and Trackpad, all have worked without fail until updating to OS X EI Capitan.
El Capitan problems with Apple Wireless Keyboard
Yes excactly the same problem. I am on El Cap 10.11.5 and still I get this problem. I solve the problem by removing the batteries and restarting the keyboard. It is so frequent that I now keep a coin by my desktop so that I can easily remove the batteries. I have used a trackpad for many years and it is only in the last 6 months or so that I have experienced this so I am not convinced that moving my prackpad away from the keyboard will help.
Hi there!
I upgraded my iMac 5K to El Capitan last week (10.11.5) and I am experiencing the same issue. I use trackpad, keyboard and mouse, all of them wireless. I fix the issue by power cycling the keyboard so far.
I am new in these forums, so not sure how to proceed: any one filed a bug for this? If not, how does one do that?
Thanks,
Julio.
we have two 27" imacs that have experienced this exact problem. my partner doesn't want to deal with the wireless keyboard issues anymore so we bought a wired keyboard and now experience no problems whatsoever. i am going to try turning off my wireless trackpad to see if this fixes the issue, but i'm not happy with apple's apparent indifference. i found this post first through https://forums.developer.apple.com/thread/18850 so it's not a rare or hidden issue. we were so angry/disappointed/irritated that we were contemplating a small claims action to sue for a refund of the $5k we spent on these two computers.
Same problem for almost a year! From release OS X El Capitan. I have iMac 5k late 2014. I also think that Magic Trackpad is a problem. When I turn it off there is no problem.
Best to try Apple's public/community forums for user-centric issues such as these - good luck.