The essential macOS solutions checklist

Do

Keep apps up to date. If updates delivered through Mac App Store aren’t set to install automatically, regularly check the store’s Updates tab, and use a Check for Updates command or check websites of apps obtained elsewhere.

Where a utility or feature of your Mac has a menu bar icon, such as Bluetooth, holding Alt and clicking that icon often reveals useful diagnostic information or menu items that are otherwise hidden.

If your Mac won’t start up properly, enter safe mode by holding as you power on. If that works, disable login items one at a time (Users & Groups preferences), and start up normally. Repeat until you find the culprit.

Learn helpful startup key combinations to diagnose problems, like resetting the memory that holds system settings, and more. Apple maintains a list of startup shortcuts at bit.ly/2jeOlLg.

Use the Utilities folder, located in the Applications folder. There’s a wealth of apps that can help diagnose and fix problems with networking, displays, passwords, and more.

Send crash reports to developers. If you use El Capitan or earlier, try Console: check lines in system.log from before a crash and copy to your app’s developer. Sierra’s Console can be less useful; consider opting in to auto-sharing reports – see bit.ly/SieCo.

Enable macOS’s firewall to boost your Mac’s defences against any unwanted connections from other computers. Turn it on in System Preferences’ Security & Privacy pane and then configure it by clicking Advanced.

Don’t

Disable Gatekeeper in Security & Privacy in System Preferences (options listed under “Allow apps downloaded from”). Though it may be annoying when it stops you installing apps from unknown sources, it’s easy enough to circumvent for one-off installs.

Use simple passwords: they make it easy for others to gain access to your Mac. Use Keychain Access’s Password Assistant (click the key button when adding a new entry) to enter passwords and get feedback on their strength.

Share user accounts. Give each person who’ll use your computer their own. This applies to iCloud accounts; to share calendars, music, and more, click Set Up Family in Users & Groups.

Make every account an administrator. Create a standard user account to reduce the possibility of harmful changes. Additionally, use System Preferences’ Parental Controls pane to further monitor your kids’ actions.

Risk losing your data. With Time Machine built in to the OS, there’s no excuse for not backing up. Particularly when external hard drives are now so affordable; a 1TB portable model can be bought for about $50.

Leave windows open when quitting apps if your startup disk is a hard drive. In System Prefs’ General pane, turn on “Close windows when quitting…” so documents don’t reopen with their app.

Run unnecessary services. If your Mac is the only computer on your network, go to System Preferences’ Sharing pane and turn off screen and file sharing at the very least.