The Mac question mark folder error could be caused by many factors. All these factors can be categorized into software and hardware issues. In this guide we will discuss all the factors and provide comprehensive software and hardware solutions to solve the flashing folder with question mark problems.
When you switch on a Mac, instead of displaying the Apple logo, the screen shows a Mac flashing folder with a question mark in the centre. If you have a pre-2015 Mac, you may hear the chime before you see the flashing folder with question mark. The Mac folder with question mark issues can be found across the Apple Mac computer products including MacBook, MacBook Pro, MacBook Air, iMac, Mac Mini and Mac Pro as they are all working on the same principle.
mac question mark folder on a MacBook Pro
The mac question mark folder is a sign that your Mac cannot locate its system boot folder. Therefore your Mac cannot load the macOS from the hard drive to the memory in order to run the macOS. The mac question mark folder error means:
* Your startup hard disk or logic board is faulty – hardware related issues.
* or the startup disk doesn’t contain a WORKING copy of macOS – software related issues.
In order to quickly diagnose and fix the mac question mark folder issues, we need to understand how an Apple Mac loads the macOS from the hard drive.
When you turn on the Mac, the CPU will perform a task named “Power On Self Test”, and then search for a “loader" from the available bootable devices such as hard drives, optical drives or USB drives. If no bootable drive is found or the found bootable drive does not have a working loader, a flashing folder with question mark will be displayed. If a valid loader is found, your Mac will display the Apple logo. The CPU then executes the codes of the loader and loads the rest of Apple’s macOS software into your Mac.
Read more: How does my MacBook power up?
We will discuss the Mac question mark folder issues in the order from easy to hard. Usually, software-related issues are easy to fix. Fixing the hardware-related issues requires some equipment such as soldering iron, hot air gun and multimeter. Also, micro-soldering skills and electronics knowledge are required.
Difficulty: Very easy
If your Mac displays a flashing question mark for a few moments but then continues to boot, there is nothing wrong with your Mac. You only need to reselect your startup disk in System Preferences. The default boot device of your Mac is NOT set to your bootable hard drive. Your Mac has to search for ALL bootable drives before getting to your current hard disk drive. This search task causes the time delay and you get the momentary flashing folder with question mark. Fix this problem is very easy.
1. Choose System Prefereeces from the Apple Menu and select Startup Disk.
2. Click the lock icon at the bottom and provide your password to unlock the windows.
3. Click the icon of the disk you want to use to start up your Mac. It’s usually named Macintosh HD.
4. Then click the Restart button.
Your Mac should now restart and boot up without the flashing folder with question mark.
Alternately, you can do the NVRAM reset or PRAM reset and your Mac will automatically pick up the right startup disk.
If your Mac stays on the flashing folder with question mark all the time, it indicates your Mac is in trouble. But don’t worry, if it is caused by a software issue, you have a good chance to fix it by yourself. Follow these steps to identify whether it is a software issue.
1. Turn off your Mac by pressing and holding the power button for at least 5 seconds.
2. Press the power button once to turn your Mac back on. Immediately press and hold the Command and Option and R keys on your keyboard to start your Mac from macOS Recovery. Keep these three keys held down until you see the Wi-Fi network screen.
3. Select a Wi-Fi network and key in the password to connect to the Internet. A copy of the macOS Disk Utilities will be automatically downloaded from Apple’s server to your Mac.
4. Upon finish download, your Mac will run the macOS Utilities and the macOS Utilities screen appears.
5. Open the Disk Utility from the macOS Utilities windows, if your disk is shown under the internal section on the top left-hand side, your Mac most likely has a software-related issue. If you don’t have any disk listing under the internal section, your Mac definitely has a hardware-related issue. This means your Mac cannot communicate with the hard disk drive at all. Jump to the hardware section below if you have a hardware issue.
6. In the Disk Utility window, select your startup disk and click the First Aid tab.
7. Click the Repair Disk button to verify and repair any issues. If Repair Disk reports issues such as bad sections, you have a hardware issue. This hardware issue is not fatal so you can still see the disk. If the data is important and you don’t have a backup, you may need a professional backup service now. If you are confident in the backup by yourself, go to the data backup section directly.
8. After your disk is successfully repaired, quit Disk Utility.
9. Choose Startup Disk from the Apple menu, select your startup disk and click restart.
You should be able to boot your Mac if your hard disk only has a mirror software issue. If you still can not boot your Mac, you may need to reinstall the macOS.
Note: If Disk Utility finds issues with your startup disk that it can’t repair, you may need to reformat the hard disk. You should back up any important data on your startup hard disk before erasing it. We discuss the backup procedure in next section.
If your macOS is not badly damaged, the “repair installation" discuss here may help you to fix the software issues. It requires an internet connection to download macOS from Apple’s server and run the macOS Utilities. If carried out carefully, all your data should be intact. If you already have a bootable external drive containing the macOS, you can speed up the process by running the macOS Utilities directly from your external drive.
If you don’t have a backup, you need to reinstall the macOS without overwriting the data. The idea is to replace your corrupted system file and fix other software issues without deleting your personal data. Follow the instruction discuss above to download the macOS from Apple’s server through a WIFI connection.
Once you are in macOS Utilities windows, choose option 2 “Reinstall macOS", and follow the on-screen instructions. The macOS will be installed into your startup disk without overwriting your data.
Note: Make sure do NOT use the option 4 “Disk Utility" to erase the disk. It is a good idea to connect the charger to your Mac before starting the installation process. In fact, the recent models of MacBook will insist that you must connect a charger before presenting you an option to proceed with the installation.
After the installation, your Mac should be boot up normally. If your Mac still gets the flashing folder with question mark, you may need to perform a fresh-installation instead of this repair installation. Of cause, you need to backup your data first.
If the repair installation discusses above cannot fix your problem, you need to fresh-install the macOS. It is always a good idea to do a fresh installation regularly. Flesh installation not only can fix all your software issues but also give you a faster, virus-free and more stable system.
If you don’t have a backup copy of your personal data, time to backup your data now. Use these steps to backup your data to an external drive:
1. Connect an external USB, Thunderbolt, or FireWire drive to your Mac. The drive needs to be the same size or larger than your current startup disk.
2. Use macOS Recovery to erase the external drive, then install macOS onto the external drive. Make sure that you select the external disk as the one you want to erase and install macOS. Take extreme care when you select the drive. Don’t select your built-in startup disk, usually named Macintosh HD.
3. After installation is finished, your Mac automatically restarts from the external drive. When Setup Assistant appears, select the option to migrate your data from another disk. Choose your built-in startup disk as the source to migrate your data from.
4. When the migration is done, complete the steps of the setup assistant. After the desktop appears, confirm that your data is present on the external drive.
Now you’ve made a backup to your external drive, follow these steps to fix your internal startup disk by performing a fresh installation:
1. Remove your external drive from the Mac. You don’t want to accidentally delete the data you have just backed up.
2. Use macOS Recovery to erase your built-in startup disk and reinstall macOS. This time, you need to select the built-in startup disk as the one you want to erase. When the installation is finished, your Mac automatically restarts from your built-in startup disk. It may take several reboots to complete the installation depending on the macOS version you are installing.
3. At the end of the installation, the setup assistant appears. You will be presented with an option to migrate your data. Plugin your external drive and wait for a while, your external drive should appear on the desktop.
4. To copy your personal data back to your startup disk, select the option in the setup assistant to migrate your data from an existing Time Machine backup or other disks. Choose the external drive as the source to migrate your data from.
5. Your Mac will restart again on completing the data migration. Verify your data before deleting the data in the external drive. It is a good practice to keep an updated copy of your valuable data regularly. If you have not yet use the Time Machine feature, use it now!
If you’re unable to erase your startup disk or reinstall macOS, your Mac most likely has a hardware issue. Make an appointment with an Apple Genius Bar or an Apple Authorized Service Provider to confirm the issue type. The technicians of these official services are trained well in solving the software issues, but with limited knowledge in hardware. They cannot repair your Mac logic board or SSD drive apart from replacing them. But they are good enough to tell whether your Mac has a software or hardware problem and the service is free. If they cannot help due to a hardware logic board issue, try a component-level (chip level) repairer to get your Mac repaired. There are very few component-level repair services available due to the complexity of the mac logic board and Apple’s repair policy. If you cannot find one in your city, you may consider posting your Mac to another city. Search for a reputable component-level repairer and get a quote before sending out your Mac.
When the HDD cable fails to transmit the electronic signals between the logic board and the hard disk drive, you will get a “mac flashing folder with question mark”. It could be caused by a faulty cable connector on the logic board or faulty HDD cable.
Examine the cable connector and make sure there is no foreign object in the connector. All the pins of the connector should be clean and corrosion-free.
Apple uses flex cable to connect the hard drive to the logic board. The flex HDD cables could be broken due to stress and bent over time. Failure of HDD cable is very common in the 13” MacBook Pro 2012 model.
When the flex HDD cable is fitted to the MacBook, it bends to 90 degrees twice on the edge of the super drive shown below. The copper wire inside the flexible plastic tends to be broken at the bent section over time. The defective section can not be seen by naked eyes. It can be detected by a multimeter (continuity test) or examined by a microscope at the bent section. If in doubt replace it with a good HDD cable.
mac question mark folder - faulty HDD cable
You can buy a new HDD cable online for only a few dollars. All Apple spare parts come with unique part numbers. The photo below shows the part number of the 15" MacBook Pro 2011 HDD cable. Check your HDD cable and order the spare part by part number so you won’t get the wrong one.
mac question mark folder - Apple HDD cable part number
Starting with macOS High Sierra (10.3), Apple upgrades the hard disk drive format from HFS+ to APFS. When you install or upgrade your Mac to High Sierra or later macOS, the installer will automatically upgrade the firmware (low-level system software stored in the ROM chip). If somehow the firmware fails to complete the update, you will get a flashing folder with question mark. This is because the firmware does not recognise the new APFS format.
To fix the firmware issue, you need to install High Sierra or later macOS again on your hard drive and your data should be intact. If you really concern your data, you may choose to put in a new SSD hard drive and install the new macOS (10.3 or later).
If all these fail to update the firmware, you can update the firmware manually. This method is also suitable for the IT department in organisations who need to update a lot of Macs’ firmware at the same time and deploy new macOS without going through the installation process individually for every Mac.
1. Put in a new SSD hard drive in a MacBook.
2. Install any macOS older than High Sierra 10.3 e.g. El Capitan or Sierra.
3. Go to AppStore and perform a software update.
4. Choose High Sierra or later macOS and continue the update
5. Your Mac will reboot and start the software update shown below.
6. Stop the update by choose file ->
7. Now you will see the new macOS file in the Application folder.
8. Open Terminal Utility and copy the following codes and enter. You will be asked to enter the admin password to complete the task.
echo “Mounting High Sierra ESD disk image…"
/usr/bin/hdiutil mount /Applications/Install macOS High Sierra*.app/Contents/SharedSupport/InstallESD.dmg
echo “Expanding FirmwareUpdate.pkg"
/usr/sbin/pkgutil –expand /Volumes/InstallESD/Packages/FirmwareUpdate.pkg /tmp/FirmwareUpdate
echo “Running Firmware Update"
sudo /usr/libexec/efiupdater -p “$PWD/Tools/EFIPayloads"
9. The firmware will be updated on the next startup, so reboot your Mac now.
10. Put back your original HDD and you will see the Apple logo. If your task is to update the firmware to many Macs at the same time, remove the SSD hard drive and put it in the next target Mac, repeat the steps 8 and 9.
Note: The above codes will compare the current firmware version of your Mac with the firmware version extracted from the macOS you have just downloaded and saved in the Applicaton directroy. If the extracted firmware is newer than the current firmware, a firmware update procedure will schedule on the next startup of the Mac.
The above picture shows that the extracted firmware is newer than the current firmware EFI version . So the firmware will be updated to version [007F0000] on the next startup. Also, it is very important that you need to stop the upgrade process after downloading the newer macOS, as this file will be automatically erased after finishing the software update. Our codes need to extract the embedded firmware from the file.
In 13” and 15 MacBook Pro A1706 and A1707 Manufactured in 2016 2017 with Tochbar, there is a connector called lifeboat to connect the SSD circuit to the CPU so the CPU can read and write data to the SSD chips by inserting the lifeboat cap. In a disaster situation when the logic board is not functional any more, we can remove the lifeboat connector cap and connect a device called a data migration tool. Therefore we can retrieve the data from the dead logic board.
mac question mark folder - faulty lifeboat connector
If somehow the lifeboat connector cap is not functional, you will get the flashing folder with question mark. Remove the lifeboat connector cap and examine it. Make sure there is no corrosion and clean it if necessary. All the pins of the lifeboat connector and the cap should be free of corrosion or dust shown below.
mac question mark folder - lifeboat connector cap removed
All the removable SSD drives are connected to the Mac logic board via the SSD sockets. If the socket is corroded, you may get a “flashing folder with question mark”.
Usually, the corrosion is caused by exposure to liquid or bug droppings. Use a small sharp knife to cut off the corrosion then use 99% alcohol and a toothbrush to clean the pins on the SSD drive and the SSD socket. If the socket is damaged so badly you need to replace the socket. You need to have micro-soldering skills to perform this task or use a professional component-level logic board service.
SSD drive and SSD socket on Mac logic board
If your hard drive is faulty, the logic board cannot communicate with it, you will get a “mac flashing folder with question mark”.
If you have a mechanical spinning hard disk drive, put your hand on the drive and switch on your Mac. If you cannot feel the vibration of the hard drive spin motor, the hard drive is dead. There is no power to the motor or the motor is dead.
If you have an SSD drive, switch on your Mac and wait for five minutes or so. Put your finger on the SSD controller chip ( the biggest chip). If the chip is cool, your SSD is dead. The SSD does not receive any power at all.
The above diagnoses are based on the assumption that your Mac logic board is good. If in doubt, get a known working Mac and try your hard drive again. If you still get a question mark folder, you have a good chance that the hard drive is faulty even though you can feel the motor spinning or SSD controller warming up.
On some 2013 to 2015 Samsung SSD drives, the SSD controller may develop crack soldering ball issues after continuing to expose to high operating temperature. If you put the drive in an oven at 180 to 200 Celsius degrees for two minutes, it might work again as the cracked balls have been joined again. If the data is very important, do not try this method, get a reputable mac data recovery service provider as soon as possible. Please note that the second attempt to recover the data from a faulty hard drive is much harder or even impossible as the first attempt already destroyed some or all the data.
Equipment needs: EPROM programmer
If something went wrong while you were updating the macOS, you may get the flushing Mac folder question mark. This is because the update program has already made some modification to the system EFI chip but failed to complete, therefore you end up with a corrupted EFI firmware.
We need to get access to a working Mac. This Mac must be the same model and same manufacture year with your one. You are going to retrieve the EFI codes from this working Mac. You need to modify the ME region (Intel Management Engine code) of the EFI codes and serial number before writing the code to your in-trouble Mac.
1. Connect the EPROM programmer to the programming port of the working Mac.
2. Read the code from the Mac and save it as a file.
3. Use a hex editor to replace the ME region with a fresh compatible ME.
4. Replace the serial number with your own Mac.
5. Write back the modified code to your in-trouble Mac
6. Power up your Mac and perform a PRAM reset.
Now your Mac should be able to boot normally to the masOS and no more flashing question mark folder.
Note: In every Mac, the Intel Management Engine (ME) of the EFI code is “married” to the individual CPU/PCH inside the Mac. This is why you need to replace the old ME with a fresh one.
Equipment needs: EPROM programmer, Hot Air Gun Rework Station
If your Mac is locked by the EFI password, you may see the flashing Mac folder with question mark. This password is different from the password that you use to set up the macOS account. The EFI password is stored in the EFI chip soldered on the logic board. It will lock the whole logic board. You can not use the option key function to guide the logic board to boot from an external HDD or simply replace the internal hard drive.
By contrast, the macOS account password is stored in the hard drive. You can get rid of the password by erasing the macOS completely or simply put another hard drive in the Mac. In other words, macOS account password protects the data in the hard drive while the EFI password prevents unauthorised access to the logic board.
There are a lot of reasons why the Mac is locked by EFI password and we are not going to address the reasons in this guide. We emphasize on how to remove the EFI lock.
There are two ways to fix this problem, replacing the whole logic board and clearing the password code stored in the EFI chip. We discuss the latter method here.
1. Remove the EFI chip from the logic board
2. Place the chip to the EPROM programmer
3. Read the EFI code and save as a file
4. Use a hex editor to open the file you just have saved.
5. Search for $ssv and replace the current row and next 12 rows with hex FF. This will clear the EFI lock code.
6. Write back the modified EFI code to the chip.
7. Solder the chip back to the logic board.
Congratulations! If you can come up to this point, you just pass the intermediate level and enter into the advanced level of fixing Mac folder question mark issues.
The following “Mac folder question mark” case studies are hardware related and require chips replacement known as component-level repair. In order to perform the repair task, you need to have the micro-soldering skill, Apple mac logic board electronic diagram ( schematics) knowledge and some equipment.
Equipment needs: EPROM programmer, Hot Air Gun Rework Station, soldering iron. Apple logic board schematics.
Computer Model: A1706 13” MacBook Pro 2016 with touch bar
Logic board number: 820-00239
When we switch on this MacBook, we get the Mac question mark folder straightaway. Then we connect an external bootable SSD drive to the mac, we can boot into macOS and everything is working fine. Base on this test, we lock-in the fault is in the SSD circuit section. The SSD chips are soldered on the logic board in this MacBook.
Open the back panel of the MacBook and examine the logic board. Remove the lifeboat cap on J9600 and clean the connector as well as the cap. Reinstall the cap and turn on the Mac, we still get the flashing question mark.
There are 8 power rails for the SSD circuit in this model. We need to measure them one by one. One of the 1.2V rail PP1V2_SSD_COLD is missing.
U9300 SSD power management chip is responsible for creating the 1.2V power rail. PICCOLO_IUVD is the enable signal to tell U9300 to create 1.2V PP1V2_SSD_COLD. When we measure PICCOLO_IUVD the voltage is 0V and is not OK. We spot something one the resistor R9350. Put the logic board under the microscope, we have found a bug dripping on the resistor and corroding it. Replace the resistor and we get the Apple logo instead of the Mac question mark folder.
Equipment needs: EPROM programmer, Hot Air Gun Rework Station, soldering iron. Apple logic board schematics
Computer Model: A1466 13” MacBook Air 2017
Logic board number: 820-00165
There is a removable SSD drive in this model of MacBook. Remove the old SSD drive and put in our known-working SSD drive, we still get the Mac question mark folder. This is confirmed that the fault is in the logic board, not in the SSD drive.
Measure all the power rails, data bus and reset control signals on the SSD connector. They are all working fine. The fault must be in the SATA control circuit in the CPU side.
There are few power rails to power up the CPU SATA controller. When we measure the PP1V05_S0SW_PCH_VCCSATA3PLL, the voltage is 0.6V. The correct voltage should be 1.05V. This power rail is for SATA clock generator inside the CPU. If this power rail missing, the CPU cannot get the SATA clock, therefore cannot communicate with the SSD drive.
Further investigation shows that the inductor L1290 is faulty. It cannot fully pass the 1.05V voltage from one end to the other end. Replace the inductor the MacBook works fine.