I like using the Activity Monitor within the Utility folder. Sometimes if your machine slows, you can see which process is the culprit and then kill it and associated processes. Easier than going into Terminal and using the UNIX commands (unless you love that). In Activity Monitor sometimes you’ll see a process doing lots of network activity sending data in and out. In that case, pull your Ethernet plug or turn off Wi-Fi and see if you regain control of your machine. Sometimes some crafty program or extension will take over your machine, on it’s own, and leave you frustrated waiting on a spinning cursor. Perhaps something picked up from a bad web site or piggybacked on a new application. Stopping your network access will allow you to clean Safari of accumulated web cookies and other junk, and any other bad apps you recently installed. Always a good idea to periodically clear out old website data, although you’ll have to re-enter logins and passwords, naturally, but it will reinforce your memory of them.
Go to Apple/Preferences/User & Groups, and under your user ID select Login Items. It will show those apps that automatically start when you login. Delete the ones you no longer want to start up automatically.
Thank you .. this is really helpful. I’m not sure how to tell that a given app is sucking up too much of the process but hope to get it figured out. I’m always afraid to delete or change anything for fear I won’t be able to log back into my computer. Gotta get over that! Thanks so much.