thisdoghunts Said:
"I ran in Safe Mode and also ran using a different User Account, result was the same (problem still existed). I also downloaded and executed Etresoft and it reported no major problem when no apps were running. With Safari only executing it reported that it was using an excessive amount of CPU."
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Three Thoughts - then a Reinstall:
- Use MalwareBytes for Mac:
Seeing that Safari is reportedly using an excessive amount of CPU, I would recommend that you run Malwarebytes for Mac. This is software that searches for malware/adware. So, scan with it and then remove what is found from the quarantine. Once removed, uninstall MalwareBytes for Mac. Then, finally, restart the Mac.
Downloads:
- Malwarebytes Anti-Malware for Mac
- Malwarebytes uninstaller
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If your CPU is getting too hot, then I am certain that too much is running in the background, from a security scan to whatever else. But, you might have an application that is not responding. If so, Force Quit It.
- Go Into: the Apple Menu
- Click: Force Quit...
- Select: an Application ending in "(Not Responding)"
- Click: Force Quit button
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See if something opens at log in that is staying open, causing too much processing to occur. Go Here: Change Users & Groups Login Items preferences on Mac - Apple Support.
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Reinstall the macOS:
As a last resort, reinstalling the macOS may be the ultimate way to go here.
- Back up your Mac: Start by Creating a Time Machine backup of your Mac, so that way you can have something to restore your Mac from, should anything go wrong with the reinstall.
- Reinstall the macOS: Nothing would be lost, it's just that sometimes changes are made to your system, and then then processes become corrupted, technically. When reinstalling, deleted files are reinstalled, and misplaced files are moved back to where they should be. Go Here: How to reinstall macOS from macOS Recovery - Apple Support.