Hi and Welcome. My Name is ***** ***** I look forward to assisting you today with your question.
What version of Mac OS X are you using ? When did this problem start ? I mean after any software updates or installation ?
Do this please. Go to System Preferences and select Keyboard. Under Keyboard, click Modifier Keys and click Restore Dafaults button.
Then click on Input Sources and what keyboard layout is selected there ?
Is the entire layout of keyboard changed ?
Go to System Preferences > Keyboard. Click on Input Sources. Click the + button and add English > British. Remove the US.
Then check. Is it still showing wrong characters ?
Go to System Preferences > Keyboard. Click on Input Sources. Click the + button and add English > British. Remove the US by clicking - button. Check keys
Your Mac can enter different characters when you depress Option + characters, Option + Shift + Characters etc
So tap on Option both of left and right a few times and does it clear ?
We can continue later. Add a bookmark of this page or add this page to your favorites, so you can get backt to later. Change it to British layout. This is to test it. You can change it back to US later.
It is possible that the option key is stuck in depressed state (inside it due to dirt or liquid). We may need to clean it.
Then it should be software related. We can try some basic troubleshooting steps when you are back
When you are back, please post a reply in here and I will get back to you.
Change the layout to British and remove US. Then check. I also want you to create a new admin account and test on that account. This will tell us whether it is related to user account or system wide and help us to move to right direction.
Ok, then talk to you on 11:30. Take Care
I will post some troubleshooting steps, so you can try when you have time.
We can run Disk Utility and see if it works or not. Turn off your Mac by holding down Power button for 10 seconds. Then turn it back on and immediately hold down Command and R keys at same time for 20 seconds and this will boot your Mac to the Mac OS X Utilities screen. From there, click Disk Utility. Select your hard disk at left column (Macintosh HD or hard disk name). Then click First Aid button and run it. Repair if asked.
Then restart from Apple menu. If that didn't work, then turn it off. Turn it back on and immediately hold down Command, Option, P and R keys at the same time for 5 seconds, then release the keys and immediately hold down Shift key for 20 seconds. Check Keyboard.
If it doesn't work, then create a new admin account and test keyboard on that account. If it works on new account, we can troubleshoot old account.
Let me know.
Sorry for the delay. Did you try my suggestions ?
What about in a new admin test account ?
Restart your Mac and immediately hold down Option key for 10 seconds and this will bring Startup manager. Select Recovery HD and press return. This will boot into OS X Utilities screen. Run Disk Utility from there
Through this mode I can give you instructions and you can take your time and do this at your convienience. There is phone support, but it is additional $20
After running Disk Utility, I want you to create a new admin user account from System Preferences > Users & Groups. Then sign out from Apple menu and sign in to new account. Test Keys. If it works in there, then we can troubleshoot old account.
It is very strange is that it isn't boot into OS X Utilities. Not sure if any key is being depressed on of your keyboard. You said you are using Logitech wireless keyboard. Can you remove the batteries from it and try with other keyboard ?
Remove the keyboard receiver adapter from yoru Mac if it is connected
One of your keyboard must be sending some key input to your Mac. This could be the reason why it is not booting into OS X Utilities. The combination to boot into OS X Utilities is Command and R. If any other keys depressed along with it (on any keyboard), it won't boot into it.
Remove the Logitech receiver adapter from your Mac and remove the batteries from the Logitech keyboard. Then test only with Apple keyboard.
If that didn't work, then remove the battery from Apple keyboard and test with logitech only.
If you have a wired keyboard there, then remove batteries from both keyboard and test with wired keyboard only. This will rule out the keyboards.
Please try my above suggestion. If there is no battery on it, then remove the receiver of Logitech keyboard from your Mac or turn it off then.