If your Mac is slowing down or crashing…
Here are a few things to try... Please backup your files…
Click here for more info.
In your System Preferences under the Apple menu…
Open Users and Groups… click the login items tab… then click and delete anything you don't need... Using the - button.
Restart… make sure the checkbox is unchecked in the restart window…
Then click the restart button… when you hear the ram chimes… immediately hold the shift key down...
This is safe boot... It may make your screen flicker and do strange things… but that is normal.
You can let go of the shift key once you see the progress bar.
If you have automatic login turned on... It will ask you for your login password. Go ahead and login.
Let your Macs sit for about a minute or two… don't open anything… then restart. That's it…
You might want to run a program like Maintenance to clean your caches and other unwanted data.
It can be found here... https://www.titanium-software.fr/en/maintenance.html
Be sure to download and install the correct version for your operating system...
Look under your Apple menu… about this Mac.
You may also want to run Malwarebytes to check for malware... It can be found here...
https://www.malwarebytes.com/mac
Hope this helps… John