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  1. Worked perfectly. Thanks. It was driving me nuts. I knew it was in my profile because another user account on this machine has the default settings.

  2. I used the terminal approach as I am often doing things in the termiinal. Allow me to be the first to tip my hat to you in 2021. Well done, sir/madam!

  3. Please help, this only works once. Every time the MAC sleeps it goes back. I ca not delete the file as it says “Permission denied”
    Any ideas, thanks very much

    1. Be sure to quit the monitor first with command q or use the menu to quit. Clicking the red point to close is not enough.
      If that does not help,
      use afterwards the terminal and remove as root with the command
      sudo rm ~/Library/Preferences/

  4. Thank you! I was so disgusted with the bugs in Catalina I started looking at getting away from Apple and going back to Windows. Activity Monitor was horrible, nothing worked. Several fixes had me looking for that plist which was not there.

    Apple needs to do a much better job on software.

  5. Thanks! Just updated to Catalina and have had to find solutions to a number of things. This was one, and your instructions worked well!

  6. Amazing, dealing with this all morning and now thanks to your info it is working !!! thank you very much!!! U R The man!

  7. Great tip, thanks so much for the help.

    Note to anyone happy using terminal:

    You can do this by just entering

    $ rm ~/Library/Preferences/

  8. Hi
    One other point to check is the column width of the Process Name. I thought that the columns were not being displayed. Somehow, the Process name column width was huge.

    Scrolling to the right showed all my columns as usuals so I only needed to reduce the width of Process Name column

    1. Thanks Peter. My “Process Name” column was also extremely wide, probably like 5,000 pixels wide (no exaggeration). I’d say people should try your hint first.

  9. Excellent, the “~/Library/Preferences/” delete worked first time for me, thank you

  10. Serhat, your solution worked perfectly! Now, what is the trick behind it? I have another Mac computer, went on to check that file and it is there as well (~/Library/Preferences/ But the Activity Monitor on that one shows all columns. Why is it that this happens randomly to some computers? and what is the reason, if you may please share. Many thanks

  11. Well, just chiming in that the problem is still happening, and the plist deletion fix still works. Apple, this is NOT simplicity…

  12. Thanks, It worked.

    For a minute I thought they had removed the columns in Activity Monitor like they removed the columns in Mail for Catalina. Perhaps to stop people accidentally stopping some process that shouldn’t be stopped.

    I was thinking next they are going to remove the columns in Finder. Then the ones in Numbers.

    At that stage, I will be leaving the Apple ecosystem.

  13. Thanks. Worked like a charm. I keep forgetting about the obvious option of deleting an app’s plist.

  14. Brilliant – I had recently upgraded to Catalina – lost the activity monitor data. Removing the plist file and everything worked.

  15. Worked a treat, thank you!
    It was important to use the ‘go to folder’, I wasn’t able to see it by navigating in finder in the usual way.

  16. this works for awhile but then the columns slide all the way to the right.This is a bug and shame on apple for allowing it.

    1. Hi.

      I followed option 2 and it puts the column back. But now I am facing the bug as you where the columns slide all the way to the right.

      May I ask if you have found any solutions to this?

      1. Seems to be a bug when you upgrade mac OS. Just swipe two fingers on the bar when the column headers used to be… and keep scrolling. Eventually you will get to the missing columns. now resize the first column back to the correct size.

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