Apple Bluetooth keyboard not typing group of letters

Stevemacses wrote:

My problem is a group of keys (M,J,K,L,I,O,U) are not typing anything.

If it is 789uiojkl, this is a well-known problem caused by having Mouse Keys turned on in your Accessibility preferences. Try hitting the Option key 5 times.

First please reset the SMC 2-3 times back, why 2-3 times....simple it does not always work the first time. If that does not work please do the following:

The following will require any USB keyboard and mouse. If you don’t have them, borrow or buy them, they are inexpensive!

1. Connect the USB keyboard and mouse to the computer.
2. Open System Preferences – Bluetooth
3. Un-pair the wireless keyboard and mouse.
4. Turn off Bluetooth
5. Restart the computer in Safe Mode per the directions in How to use safe mode on your Mac - Apple Support
6. Restart the computer normally.
7. Open System Preferences – Bluetooth
8. Turn on Bluetooth
9. Re-Pair the wireless keyboard and mouse.

10.  Unplug the USB keyboard and mouse and begin testing the wireless devices again.

The next step is the following:

It will help us get a good idea of what is causing your problem if you provide a report of your system, that way we do not have to play 20 questions with you. The report we are requesting does NOT provide any personal information and is extremely safe to use. Please navigate to www.Etrecheck.com and download the free version of EtreCheck. Once you have you downloaded the app and installed it, please run the report and save it.

When you have your report, you can attach it when you reply to this message and we can then review it and help you determine what is needed to get your system running well again.

For instructions on how to download your EtreCheck report and attach it to your reply to this message please click How to use the Add Text Feature When Post… - Apple Community

Your computer is a mess. Below is a list of things you need to fix:

Security updates disabled - Security updates are disabled. This computer is at risk of malware infection. This means you need to boot into the Recovery Partition (Command + R on startup) and install Mac OS to fill in the parts of Mac OS that you have damaged and removed.

Lets start with that and then restart normally and test your keyboard. If the problem is still there, test with any wired keyboard. If the replacement keyboard works that points the finger at your wireless keyboard, in short replace it.

Glad Tom figured it out for you!