Left shift key doesn't work in Catalina on 2 computers

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Level 1

4 points

Left shift key doesn't work in Catalina on 2 computers

Hi,

I have two computers running Catalina: a macbook pro from 2012 and an iMac from 2013.

Both computers have the LEFT SHIFT key not working, so when I press SHIFT and a letter, it doesn't print it upper case.

Moreover, I can't access any characters that need the shift key. I can get around this using the RIGHT SHIFT key, but it is annoying.

On top of this, the Macbook pro has another problem, though. The characters are from another layout (Finnish maybe?) and changing the layout to the UK keyboard or US international does nothing.

As I thought that that both problems could be related to software, I wiped out the macbook pro and re-installed the original OS and didn't do anything.

Just for your information, this behavior affecting both computers happens for all software and even when logging in to the computer. I have to use the right shift for the password to be accepted.

Any ideas? I need help.

Kind regards,

Pedro

iMac 21.5″

Posted on Mar 7, 2025 3:45 AM

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Answer 1

Top-ranking reply

pcardoso73 Author

Level 1

4 points

Mar 7, 2025 7:11 AM in response to Tom Gewecke

Hi,

Sorry for my late reply.

Please find attached a picture with the alphabet. Btw it's not Finnish or any orther language, I think.

Connecting an external keyboard works fine, so I wrote the alphabet and numbers with the external keyboard and with the macbook pro keyboard.

Another important aspect is that this started when I changed the touchpad, since mine was broken.

Kind regards,

Pedro

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Answer 2

Tom Gewecke

Level 10

121,992 points

Mar 7, 2025 7:19 AM in response to pcardoso73

pcardoso73 wrote:

Btw it's not Finnish or any orther language, I think.

Right, that's just normal output when the machine thinks both shift and option are always depressed. So it may indicate hardware damage to the keyboard.

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Answer 3

Tom Gewecke

Level 10

121,992 points

Mar 7, 2025 4:23 AM in response to pcardoso73

pcardoso73 wrote:

the Macbook pro has another problem, though. The characters are from another layout (Finnish maybe?) and changing the layout to the UK keyboard or US international does nothing.

Could you give examples of the wrong characters being produced?

Have you made sure that at System Preferences > Keyboard > Input Sources you have only one item on the list, and the name of that item is British?

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