Keyboard going berserk, typing on its own

Hi patricia88,

Thank you for using the Apple Support Communities! We understand you are experiencing an issue on your iMac, where letters are appearing without your input. We can certainly see how impacting this is, especially when you're trying to get set up for work-related tasks. Let's work together and help find a solution for you.

You've taken some good steps so far. Our next suggestion will be to try the steps in this article: If your Apple keyboard doesn't work - Apple Support. Please note, there is a section for a wireless keyboard, and a USB keyboard. Choose which section relates to your type of keyboard. The article steps relate to the keyboard not working in general. For your specific issue, after taking these steps, you should test for resolution by placing your iMac back into sleep, and then wake it to see if the keyboard continues entering letters on its own.

If the behavior continues, I'll have you try the following resets below. These resets do not affect your personal data. Be sure to test for resolution after resetting the SMC, before you reset the NVRAM:

-How to reset the SMC of your Mac - Apple Support.

-Reset NVRAM or PRAM on your Mac - Apple Support.

Keep us posted on the results. Regards.

patricia88,

Thank you for taking the time to perform those steps. We are going to perform further steps to help isolate the issue.

-Are you using a USB keyboard, or a wireless keyboard with your iMac? Do you happen to have another keyboard you can test with your iMac? This will be important to help us rule out the issue being related to the communication between your iMac and keyboard.

Then, let's have you boot up into safe mode. It’s a way to start up your Mac so it performs certain checks, repairs, emptying of system cache, and prevents some software from automatically loading: How to use safe mode on your Mac - Apple Support. Once in safe mode, allow your iMac to go into sleep, and then try waking it as you normally do, to see if the keyboard behavior continues. Sometimes safe mode can successfully resolve some issues. With this being said, after testing in safe mode, restart and log in as normal to see if that helps resolve the issue.

If the issue remains, we will have you test a new user account next, to isolate if this is a user-specific issue, or a system-wide issue. Here’s how: How to test an issue in another user account on your Mac - Apple Support. Once in a new user account, do the same thing to test; allow your iMac to go into sleep, and then wake it as normal to test the keyboard behavior.

We look forward to hearing back from you with these results. Thank you.