Why is my Mac working so slowly?

Most likely your system is in CPU safe mode. This is when the systems SMC sees a defect and reduces the CPUs clocking and ramps up the fan.

Lets see if you can discover an error running the onboard diagnostics. Restart your system and press the D key did you get any error codes & messages?

Mac startup key combinations

Do you have many programs running in the backupground?

Or you may check whether the system and hardware are needing upgraded. And the hard drive space, (this is important), make sure there is enough free disk space.

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