Before undertaking any of the more time consuming solutions below, these are a few fundamentals to get you started.
- Consider how long you've been waiting. Patience is key. Sometimes a Mac is doing a software update, but you don't realize because there's no hallmark "Estimated time" and a grossly incorrect approximation under it. Give it another 15 minutes.
- Put a sticky note or some tape on the display with its edge aligned with the progress bar so you can tell if it's made any progress.
- If your waiting isn't fruitful, perform a force shutdown of your Mac. Press and hold the power button for fifteen seconds. Don't be fooled by a black screen, keep holding for a few seconds even past that. Then try and power back up again.
- Disconnect all peripherals before power on.
- Perform both an SMC and an NVRAM reset. This clears many settings used during startup and can correct a faulty configuration.
- Run a repair on your startup disk using Internet Recovery.
- Run Apple’s Diagnostic Suite to check for any blatant errors. Be aware that this test is designed to optimize quick results. Trust a failure, but not a pass.
Software Corruption or Conflict
During the course of using your Mac, something in the ones and zeroes that makes it run might have been lost, or changed in a way that causes inefficiencies. This is commonly a result of a botched update, an app which conflicts with functionality, or even a malicious piece of software.
- Start up in Safe Mode. This minimizes startup processes and attempts some basic repairs. Press an holding Shift immediately after the power button during startup. You may need to log in twice in Safe Mode. Safe Boot will appear in the upper right corner of the login screen.
- Note: Apple Silicon based Macs use a modified process for this. When the machine is powered down, press and hold the power button until "Loading startup options" appears on screen. Select your disk, then press and hold shift to present the "Continue in Safe Mode" option.
- If your Mac boots all the way in Safe mode, it's likely third party software causing the hang during normal boot. Narrowing this down can be hit or miss
- Uninstall apps that were installed or updated recently then retest. If you don't know what changes were made recently, check the System Information App. The "Software" section has an entire list of installations that can be sorted chronologically.
- As a last resort, perform a reinstall of the operating system using recovery mode. This should not cause any data loss, but it's always good to be cautious. Check your backups first. (refer to recovery guide if no backup)
- Erase your disk and reinstall the OS to rule software out entirely. Refrain from restoring any items from your backup until you know the issue is resolved.
Storage Is Full
Have you been getting warnings that your device is running low on storage? It’s easy to ignore, but computerized devices also need some free space to operate properly. Think of it like your sock drawer. You can squish any number of additional pairs of socks in, but eventually your drawer will stop closing. Your computer might be stuck in this same situation; constantly needing to rearrange to find a way to fit it all. This incessant reshuffling can put your computer in a bind.
- Check the amount of storage you're using in Recovery Mode. The Disk Utility option will give you a read on this.
- Run a repair on your startup disk. Using Internet Recovery is best, but not mandatory. This might clear up stubborn errors since your disk is not in use. Internet Recovery runs from entirely from RAM.
- If your storage is full, there are still ways to clear it even the Mac won't boot. Most methods for data recovery also apply to data removal. Transfer files off your drive, or delete unnecessary ones altogether to free up space.
Missing Sensor Data
Most computerized devices are littered with a bevy of sensors which inform the system about localized temperatures or the voltage or current of connected circuits. If sensor data is missing, Macs kick into a protective mode. In the mind of a Mac, lack of sensor data means everything could be on fire.
- This issue is typically accompanied by high fan speeds, even if hardware temperatures are low.
- Your Mac will likely boot in this state given enough time, but it will be extremely slow. Common culprits are the trackpad and battery. Run Apple Diagnostics to attempt to narrow down the issue.
This occurs most frequently on Unibody MacBooks which make use of the tried and true Hard Drive Disk, or HDD. They have been around since the early days of computing, are comparatively inexpensive, and can last for many years if well taken care of. However laptops are meant to be mobile and the mechanical nature of these drives means they are prone to failure.
- Run Apple Diagnostics or Hardware Check to find blatant hard drive failure. More thorough hard drive testing is often necessary to uncover issues, so trust a failure here, but not a pass.
- Signs of storage failure include overall sluggishness, inability to access certain files, intermittent ability to boot.
- Clicking, beeping, scratching, buzzing or rattling coming from the area to the right of the trackpad point to mechanical failure of the drive. If any of these sounds are present, open the Mac and power on again to isolate the noise to the storage drive and not a fan or the disc drive.
- Check to see if your drive is detected the Disk Utility function of Recovery Mode. If not, it’s likely to need replacement. Find the Guide for your model and remember you’ll need to reinstall macOS on the new drive.
- Pro Tip: Consider replacing the HDD with a Solid State Drive, or SSD. This is the modern standard for laptop storage. They are more energy efficient, generate less heat, and support faster speeds. It’s the best way to revitalize an older computer!
Faulty Storage Connection
Even if your hard drive is working properly, if it cannot communicate with the logic board, it’s not much good. It would simply be sending ones and zeroes into the ether.
- Models with an HDD installed will have a cable to carry the signal to the board. These cables can wear out leaving a good hard drive with no way to communicate. If there is any double as to which component is at fault, replace both the drive and the cable.
- If you have a model with a factory installed SSD, these connections are made directly to the logic board via a soldered on slot. Skip ahead to the “Faulty Logic Board” portion of this page for more info.
Faulty Logic Board
The logic board is the hub for the vast majority of a MacBook’s functionality. Any number of the small components on the board may have failed or become damaged. Logic board fault is a safe assumption of cause if nothing else on this page has worked.
- Check for obvious signs of a board issue - burned or cracked components, liquid residue, corrosion or bend. If there are signs of liquid, there’s still hope your Mac can be resurrected.
- Replacing the logic board is often the most practical solution for a DIYer whose board has failed. If your board is at fault, and you need data, you still have options.
- If you’re feeling especially curious, the tiny components on the board can be repaired with microsoldering. It is an art unto itself, but a worthy endeavor for those who are adventurous. Interested? Check out this intro! If you can't do this sort of repair yourself, give your local repair shop a call and see if they can help. Even if they can’t, they may be able to recommend someone who can.