Not Working on Mac? Fixes for Common Issues

If something is not working on your Mac, the fix is usually straightforward: start by quitting the app and reopening it, then restart your Mac, and check for software updates. If the problem persists, the specific steps below address the most common culprits—from unresponsive apps to Wi-Fi and Bluetooth failures—so you can get back to work quickly.

Why Things Stop Working on a Mac

Macs are generally reliable, but they are not immune to glitches. The most common reasons an app or feature stops working include:

Software bugs – A recent update may have introduced a conflict, or an older app may not be compatible with the latest macOS version.
Resource exhaustion – Too many apps open at once can fill memory or CPU, causing slowdowns and freezes.
Corrupted preference files – Settings stored in plist files can become corrupted, leading to odd behavior.
Peripheral conflicts – A connected device, like a printer or external drive, can interfere with system functions.
Network issues – Wi-Fi, Bluetooth, or VPN settings may be misconfigured or temporarily broken.

Understanding the cause helps you choose the right fix, but starting with the basics often resolves most problems.

First Steps: The Universal Fixes

Before diving into advanced troubleshooting, try these three steps in order. They resolve a surprising number of issues with minimal effort.

Force quit the problematic app – Press Command + Option + Escape, select the app, and click Force Quit. This is safe for unsaved work only if the app is truly stuck; otherwise, try quitting normally first.
Restart your Mac – Choose Apple menu > Restart. This clears temporary memory and resets background processes. If the Mac is frozen, hold the power button for about 10 seconds until it turns off, then press it again to turn on.
Check for updates – Go to System Settings > General > Software Update and install any pending macOS or app updates. Restart again after updating.

If the problem remains, move on to the specific sections below.

App-Specific Problems: Won’t Open, Crashes, or Freezes

When a single app misbehaves but the rest of the system works, the issue is likely tied to that app.

App won’t open – Right-click the app in the Dock and select Quit (if it shows as running), then reopen it. If it still fails, check if the app is compatible with your macOS version by looking at the developer’s website or the App Store page.
App crashes on launch – Delete the app’s preference file. Go to Finder > Go > Go to Folder (Shift+Command+G) and type ~/Library/Preferences/. Find the file with the app’s name (e.g., com.example.app.plist) and move it to the Trash. Restart the app—it will create a fresh preferences file.
App freezes – If the app stops responding, use Force Quit as described above. After reopening, if it freezes again, try resetting the app’s cache (if the app has that option) or reinstalling it.
App is slow – Open Activity Monitor (in Utilities folder) and check the CPU and Memory tabs. If the app is using high CPU, it may be stuck in a loop; quit and reopen it. If memory is low, close other apps.

For apps downloaded from outside the App Store, a quick reinstall often fixes corruption. Drag the app to the Trash, then download it again from the developer’s site.

Wi-Fi and Bluetooth Not Working

Network and connectivity issues are common and often easy to fix.

Wi-Fi

Turn Wi-Fi off and on: Click the Wi-Fi icon in the menu bar, select Turn Wi-Fi Off, wait a few seconds, then turn it back on.
If that fails, restart your router and modem by unplugging them for 30 seconds, then plugging them back in.
Forget the network: Go to System Settings > Wi-Fi, click Details next to your network, then Forget This Network. Reconnect by selecting the network and entering the password.
Reset the Wi-Fi service: Go to System Settings > Network, select Wi-Fi, click the ellipsis (…) and choose Set Service Order or Make Service Inactive then active again. Alternatively, delete the Wi-Fi service and re-add it.

Bluetooth

Turn Bluetooth off and on from the Control Center (click the Bluetooth icon).
Remove and re-pair the device: In System Settings > Bluetooth, hover over the device, click the “x� to forget it, then put the device in pairing mode and add it again.
Reset the Bluetooth module: Hold Shift + Option and click the Bluetooth icon in the menu bar, then select Reset the Bluetooth module. (This is hidden; if you don’t see it, skip this step.)
Check for interference: Move the Bluetooth device closer to the Mac, and avoid USB 3.0 hubs or cables near the Mac, as they can interfere.

Mac is Slow or Unresponsive

If the entire system feels sluggish, it’s often due to low storage, too many startup items, or a runaway process.

Free up storage – Go to Apple menu > About This Mac > Storage. If the bar is nearly full, delete large files or use Storage Management to offload files to iCloud. Aim for at least 10-15% free space.
Manage startup items – Go to System Settings > General > Login Items. Remove any apps you don’t need at login to speed up boot and overall performance.
Check Activity Monitor – Look for processes using high CPU or memory. If a specific process is stuck, select it and click the “x� to quit it.
Reset SMC and NVRAM – If the Mac is still slow, resetting the System Management Controller (SMC) and Non-Volatile RAM (NVRAM) can help. The steps vary by Mac model (Intel vs. Apple silicon). For Apple silicon Macs, simply restart the Mac; the SMC reset isn’t needed. For Intel Macs, shut down, then hold Shift + Control + Option and the power button for 10 seconds, release, then turn on. To reset NVRAM, shut down, then press power and immediately hold Command + Option + P + R for 20 seconds.

Common Errors and Their Fixes

Here are a few specific error messages you might encounter:

“The application can’t be opened� – This often appears for apps downloaded from the internet. Go to System Settings > Privacy & Security and look for a message about the app being blocked; click Open Anyway if it’s there. Alternatively, right-click the app and select Open from the context menu.
“You don’t have permission to open� – Check the file or app’s permissions: Select it in Finder, press Command + I, and expand Sharing & Permissions. Ensure your username has “Read & Write� access.
“The disk was not ejected properly� – This is a warning, not a failure. It means an external drive was unplugged without ejecting. To avoid data corruption, always eject drives before unplugging.
“Your computer restarted because of a problem� – This is a kernel panic. Note the error details, then restart. If it happens repeatedly, check for incompatible hardware or software, and consider reinstalling macOS.

When to Reset macOS or Seek Help

If you’ve tried all the above and the issue persists, you may need to reinstall macOS. This does not erase your data (unless you choose to erase the disk), but it’s a good idea to back up first with Time Machine or another backup method.

Back up your Mac to an external drive.
Restart and hold Command + R to enter Recovery Mode (on Apple silicon, hold the power button and select Options).
Choose Reinstall macOS and follow the on-screen instructions. This will install a fresh copy of the operating system over your current one, keeping your files and settings.

If you’re not comfortable doing this, or if the problem is hardware-related (e.g., a faulty keyboard, screen, or battery), contact Apple Support or visit an Apple Store. For issues with third-party hardware, check the manufacturer’s support first.

Frequently Asked Questions

Why does my Mac keep freezing?

Freezing can be caused by insufficient RAM, a specific app hogging resources, or a failing hard drive. Check Activity Monitor for high memory pressure, and run First Aid in Disk Utility to check the drive’s health. If the problem persists, try booting in Safe Mode (hold Shift during startup) to see if it’s a third-party extension.

How do I force quit an app on a Mac?

Press Command + Option + Escape to open the Force Quit window, select the app, and click Force Quit. If the app is completely frozen and the keyboard shortcut doesn’t work, press Control + Option + Command + Power to restart the Mac immediately.

Why won’t my Mac connect to Wi-Fi after an update?

macOS updates can sometimes reset network settings. Try forgetting the network and reconnecting, resetting the Wi-Fi service, or restarting your router. If that fails, check if other devices connect to the same network; if they do, the issue is with your Mac’s network configuration.

Can I fix a Mac that won’t turn on?

First, check the power adapter and cable for damage, and try a different outlet. If using a MacBook, try resetting the SMC (for Intel models) or just letting it charge for a few minutes (for Apple silicon). If the screen stays black but the Mac sounds like it’s running, try an external display or reset NVRAM. If nothing works, it may be a hardware issue.

How do I clear the cache on my Mac?

You can clear user caches by going to Finder > Go > Go to Folder and typing ~/Library/Caches. Delete the contents of folders you don’t recognize, but be careful—some apps may recreate their caches automatically. For system caches, restarting your Mac is usually enough; avoid deleting system files unless you know what you’re doing.

Why is my Mac’s battery draining so fast?

Check System Settings > Battery to see which apps use the most energy. Close background apps, lower screen brightness, and turn off Bluetooth when not in use. If the battery health is below 80%, consider replacing the battery.

General steps for current mainstream versions; menus can differ by device and version. See the disclaimer or report an error.

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