Apple has increasingly made it hard to mess with macOS system files. That’s true whether you intentionally want to extend macOS’s functionality or if a malicious party is trying to install and activate a virus. However, many system components and all Apple and third-party apps rely on preferences and other files to store your custom settings, caches for work in progress, and other data. If those files corrupt, macOS may be perfectly fine, but you can’t get anything done in an app or your account.

Once you’ve gone through troubleshooting your Mac within your account that doesn’t seem to improve matters, the next big leap before reinstalling macOS is to set up a fresh macOS user account. From this account, you can test hardware, like your Wi-Fi or ethernet adapter; add printers and scanners; or run third-party software that keeps crashing on launch.

Because a fresh account typically contains nothing that would already be corrupted, you can isolate whether a problem is in your everyday user account or a system-wide issue–maybe even hardware related.

Here’s how to set up a fresh, new user account:

• Open "System Settings..." from the  Apple menu

• Go to "Users & Groups"

• Click the "Add User..." button

• Enter your password if prompted

• Choose whether to create a Standard or Administrator account, give it a name, password, and hint, and click "Create User"

When making the account, what kind should it be?

Create a Standard account if you want to test a problem from the perspective of a user without any extra privileges.

Create an Administrator if that’s your normal account type–that’s typical–and you’re trying to perform an apples-to-apples comparison.

• Choose  Apple menu > Log Out [name]

• At the login screen, select the new account, enter the password, and click the arrow to log in

Now you can check if your problem persists.

When you’ve debugged your problem, you can get rid of the account. You must be logged in using an Administrator account to do this.

Your Mac includes a built-in tool called Apple Diagnostics (formerly called Apple Hardware Test). This tool will be handy if you are dealing with a hardware issue and not a software issue. You can use it to find and diagnose issues with your Mac’s internal hardware such as the Wi-Fi hardware, the Bluetooth hardware, Touch ID, the fan, or the power adapter, etc.

Prepare your Mac

• If you can install the latest macOS updates (https://support.apple.com/en-us/108382)
• Disconnect all external devices except keyboard, mouse, display, Ethernet connection and connection to AC power
• Determine if you have an Apple silicon Mac or an Intel Mac, go to the  Apple menu > About This Mac to find out (on a Mac with Apple silicon, About This Mac shows an item labeled Chip, followed by the name of the chip, on an Intel-based Mac, About This Mac shows an item labeled Processor, followed by the name of an Intel processor)
• Shut down your Mac (if you can't shut it down normally, press and hold its power button for up to 10 seconds, until your Mac turns off - every Mac has a power button; on laptop computers that have Touch ID, press and hold the Touch ID button)
• Turn off your Mac, then wait a few seconds for your Mac to completely turn off

On an Apple silicon Mac

• Press and hold the power button on your Mac (on laptop computers that have Touch ID, press and hold Touch ID)

• As you continue to hold the power button, your Mac turns on and loads startup options

• When you see Options, release the power button

• Press and hold Command (⌘)-D on your keyboard until your Mac restarts

On an Intel Mac

• Turn on your Mac, then immediately press and hold the D key on your keyboard as your Mac starts up (if using the D key doesn't work, press and hold Option (⌥)-D at startup instead)

• Release the key when you see a progress bar or you're asked to choose a language

Run Apple Diagnostics

Follow the onscreen instructions, which vary based on your Mac, the version of macOS that it’s using, and whether certain parts of your Mac have been repaired or replaced.

As you follow the onscreen instructions:

• If your Mac isn’t already connected to the internet, you’re asked to choose a Wi-Fi network, or you can use an Ethernet cable to connect to your network

• If asked to review terms and conditions, you might be given the option to run diagnostics offline (in that case, click Run Offline)

• In macOS Tahoe 26 and later, you’re asked to choose a specific diagnostic to run, such as a diagnostic for your built-in display, keyboard, or trackpad; in earlier versions of macOS, this is automatic

When testing is complete, Apple Diagnostics shows the results. If you see one or more reference codes and need more explanation, refer to the list of Apple Diagnostics reference codes (https://support.apple.com/en-us/102334).

If you can't use this information to resolve the issue on your own, you might need service (https://getsupport.apple.com/?caller=kbase). Provide the reference code you receive from the test when taking your Mac to an Apple Authorized Service Provider, Apple Store, or an Independent Repair Provider. Genuine Apple parts are also available for out-of-warranty repairs through Self Service Repair (https://support.apple.com/self-service-repair).

This can be especially helpful if you're pretty certain that your Mac's the problem, not the printer (if your other computers can print just fine). You'll want to use this only as a last resort, though, because you'll have to set up all of your printers and scanners again.

Here's how you do it: 

• Open "System Settings..." from the  Apple menu
• Go to "Printers & Scanners"
• Right or Control click on any listed printer
• Choose "Reset Printing System..." and click "Reset"
• Wait for your Mac to complete the task and after it's finished, click the "Add Printer, Scanner, or Fax..." button to add back your printer(s)

If you hold down the Option (alt) key and click the Wi-Fi icon in the menu bar, it will  provide you with details about your router and the network you're using. The items in gray are all pieces of additional information seen only in this mode.

• IP Address: This is your computer's IP address.

• Router: Your router's IP address. You can type this into your browser to access your router's web interface.

• Security: Your router's security. Most routers on the market offer WPA2 Personal, and it keeps your network encrypted.

• BSSID: This is your router's MAC, or hardware address. It acts as an identifier for your router that lets it talk to other network-connected devices.

• Channel: This is your WLAN channel, and it determines which radio frequency the router uses to transmit information.

• RSSI: Received Signal Strength Indicator measures how well a device "hears" a signal from the router. It's useful for determining if you have enough signal to get a good wireless connection.

• Noise: This measures how much radio noise is interfering with the RSSI signal. Signal-to-noise ratio is a measure used in science and engineering that compares the level of a desired signal to the level of background noise. It is defined as the ratio of signal power to the noise power, often expressed in decibels.

• TX Rate: The transmit rate is the speed of the data that is transmitted between your router and your computer. Right now I have a speed of 450 Mbps.

• PHY Mode: This is the wireless protocol that the router uses, according to the IEEE 802.11 wireless standard.

• MCS Index: This number corresponds to the protocols uses to encode the radio signal.

Make sure you have the following:

Lightning cable: You will need it to establish a wired connection between your Mac and the Magic Keyboard, Trackpad, or Mouse. You will also need a USB hub if the Lightning cable has a USB-A port on one end and your Mac only has USB-C ports.

Wired keyboard or mouse: Since your wireless Magic accessories are not working, you will need to directly plug in a wired keyboard or mouse to navigate around your Mac. Of course, you don’t need these if you are troubleshooting the connection issue on your MacBook.

Fix Magic Keyboard, Trackpad, or Mouse not working when you power on your Mac.

After you switch on your MacBook, its built-in trackpad and keyboard are ready to use the moment you see the Lock Screen. However, when you boot up your desktop Mac, it takes a moment for the wireless Magic Keyboard/Trackpad/Mouse to become available for use. When you enter the password and go to the Desktop, you will again have a brief moment of downtime until the accessories starts working.

Both these short connection wait times are a normal occurrence. However, if your Magic Keyboard, Trackpad, or Mouse are not connecting automatically to your desktop Mac and you have waited for a while, just connect them with a Lightning cable, and it should become available for use. Leave your Magic accessory connected to your Mac via a cable for a minute or two. After that, you can disconnect the cable, and the accessory will continue to work wirelessly. You can also force your Mac to shut down using its power button, wait for a while, and then power it back on. It should auto-connect to your Magic Keyboard, Trackpad, or Mouse.

What to do if your Magic Keyboard, Trackpad, or Mouse has suddenly stopped working?

In rare cases, your keyboard, trackpad, or mouse may stop working midway after losing connection or going out of battery. Here are all the effective tips to fix it.

Plug the accessories. If you get an alert when your Magic Keyboard, Trackpad, or Mouse battery gets critically low, simply connect it to your Mac with a cable, and you can start using it. You can check the battery percentage of it by going to the Bluetooth section in macOS Control Center or using the Batteries widget.

Restart your Magic accessory. Turn off your Magic Keyboard, Trackpad, or Mouse using the small power button and wait for at least 30 seconds. After that, flip the switch back on and wait once again for it to connect automatically to your Mac. Of course, make sure your Mac’s Bluetooth is enabled in Apple menu > System Settings... In case auto-connect doesn’t work, connect it manually from Apple menu > System Settings... > Bluetooth.

Restart your Mac. Random glitches in macOS can cause all sorts of trouble, including issues between your Magic Keyboard, Trackpad, and Mouse. So, simply restart your Mac using the wired mouse, and hopefully, the problem will go away. You can also force your Mac to turn off by holding the power button for a few seconds until the screen goes black. After that, wait for about a minute, and then press the power button once to turn it back on.

Toggle Bluetooth off and on. You cannot turn off Bluetooth on your desktop Mac if the Magic Keyboard and Magic Trackpad/Mouse are connected to it. So, connect a wired keyboard and mouse to your Mac and then go to System Settings to turn Bluetooth off and back on.

Forget the accessory and connect again. If the problem continues, you should forget the Magic Keyboard, Trackpad, or Mouse from Mac’s Bluetooth settings and then reconnect it. Grab your Lightning cable and follow these detailed steps on your Mac with a wired keyboard and mouse connected to it:

• Open Apple menu > System Settings... and select Bluetooth
• Click the info button (i) next to your Magic Keyboard/Trackpad/Mouse and hit Forget This Device > Forget Device
• Turn off your Magic Keyboard/Trackpad/Mouse using its power switch, and then restart your Mac
• Lastly, turn on your Magic Keyboard/Trackpad/Mouse and go to Apple menu > System Settings... > Bluetooth to connect it to your Mac

This step should address connection issues, and now your Magic accessory will work as intended.

Also, don't forget to update your Mac. If your Mac is not running the latest version of macOS, go to Apple menu>  System Settings... > General > Software Update to download and install the newest version of the operating system.