Why Won't My Computer Boot?
Common Windows & Mac Boot Problems and How to Fix Them
Is your computer not booting, or does it turn on but fail to start Windows or macOS? A computer that won’t boot can be caused by a failed SSD or hard drive, corrupted system files, a faulty update, boot configuration problems, RAM or other hardware faults.
The symptoms you see during startup can provide important clues about the cause. In this guide, we explain the most common computer boot problems, what you can safely check yourself, and when professional diagnosis may be needed.
A computer that won’t boot does not necessarily need to be replaced. The problem could be caused by a failed SSD or hard drive, corrupted system files, a boot configuration problem, a faulty update, memory or other hardware, or simply an incorrect startup disk.
The symptoms you see during startup can provide important clues about what has gone wrong.
In this guide, we explain the most common reasons why Windows PCs and Macs won’t boot, what you can check safely, and when professional diagnosis may be needed.
Common Symptoms of Computer "Won't Boot"
The computer has no power
No lights, fans or sounds, power button appears to do nothing?
May indicate a power supply (PSU), battery problem of laptop, charger, motherboard or other hardware problems.
The computer turns on but the screen has no display
Fans or lights may be working, but nothing appears on the screen.
Possible display connection, monitor, RAM, graphic card or motherboard issues, and the RAM issue is very common.
It gets stuck on the Windows or Apple logo
The operating system starts but gets stuck during startup
Common causes include system files corruption, failed updates, drivers or storage problems
It keeps restarting
The computer starts, shuts down and then starts again.
May indicate a Windows/MacOS problem, hardware fault, overheating or failed storage
Windows shows a blue screen
Windows detects a serious error during startup
The cause could be hardware, drivers, system files or a recent software change
Mac shows a flashing question-mark folder
Mac is trying to boot but stuck there with a flashing question-mark folder
This generally means the Mac cannot find a usable startup disk or operating system.
"No boot device" or "Operating System not found"
The computer cannot find a drive containing a bootable operating system
The SSD/HDD, boot configuration or Windows installation may need attention
Common Causes of a Computer Not Booting
- Failed Hard Drive or SSD — Storage failure is one of the most popular causes of boot problems.
- Corrupted System Files — Important system files may have become damaged.
- Failed Windows Update or macOS update — An interrupted or unsuccessful update can prevent normal startup.
- Boot configuration problems — Windows may have damaged boot configuration data or related startup information. Microsoft identifies corrupted system files and boot configuration problems among issues that Startup Repair can address.
- Faulty drivers or software — A newly installed driver or program can sometimes prevent Windows from starting.
- RAM or other hardware problems — Memory, motherboard, graphics or other components can cause startup failures.
- Incorrect startup disk — The computer may be trying to start from the wrong drive.
- BIOS/UEFI or hardware configuration changes — Changes to boot mode (security boot), storage settings or other firmware settings can affect startup.
What to Do When Your Computer Won't Boot
On Windows
These troubleshooting steps apply to Windows 10 and Windows 11 PCs, laptops and all-in-one computers.
Try these steps before considering a reinstall:
1. Check the basics- Make sure the computer has power.
- Disconnect unnecessary USB devices and external drives.
- If possible, check whether the SSD/HDD is detected in BIOS/UEFI.
- Use Startup Repair to automatically check for common startup problems.
- Try Safe Mode if you suspect a driver or software problem.
- If the problem started recently, System Restore may help.
- If the SSD/HDD is not detected, the problem may be hardware-related.
- If the drive is failing, avoid repeatedly attempting repairs that could make data recovery more difficult.
- If important files are stored on the computer, consider checking the drive and securing the data before reinstalling Windows.
On a Mac
Including macOS versions such as Ventura, Sonoma, Sequoia and Tahoe, whether running on a MacBook, iMac, Mac mini, Mac Studio or other Mac computer.
Try these steps before considering a reinstall:
1. Check the basics- Make sure the Mac has power.
- Disconnect unnecessary USB devices and other accessories.
- If possible, try a wired keyboard when starting into macOS Recovery.
- Flashing question-mark folder — The Mac cannot find a usable startup disk.
- Prohibitory symbol — macOS cannot start normally.
- Apple logo or progress bar stuck — macOS may be unable to complete startup.
- Blank screen — Further hardware or software diagnosis may be needed.
- Open Disk Utility and check whether the internal drive is detected.
- Run First Aid if appropriate.
- Reinstall macOS only after considering the condition of the drive and your important data.
- If the internal drive is not detected or you have important files, avoid erasing the drive until the data situation has been assessed.
When Should You Stop Troubleshooting?
- The hard drive (or SSD) is not detected
- The drive is making unusual noises (risk of permanent data loss)
- The computer repeatedly restarts
- Windows reports that the drive cannot be repaired
- macOS Disk Utility cannot see the internal drive
- The computer has recently suffered a drop or liquid spill
- Important files are stored on the computer
- You have already tried Startup Repair or Recovery without success
- You are unsure whether a repair will erase your data
Common questions
Why won't my computer turn on?
Can a failed SSD cause a computer not to boot?
Can a Windows update stop my computer from booting?
My Mac shows a flashing folder with a question mark. What does it mean?
Will reinstalling Windows fix a computer that won't boot?
Can you fix my computer without losing my files?
Don't Reinstall Windows or MacOS Too Quickly
Reinstalling the operating system can sometimes fix a boot problem, but it should not always be the first step.
If the real problem is a failing hard drive, damaged hardware or an underlying storage issue, reinstalling the operating system may only hide the problem — and it can put important files at risk.
If you have important photos, documents or business files on the computer, please backup first!!! And check the condition of the storage drive before formatting or reinstalling.
Need more assistance? Contact us now so that we can help you check the situation and work out a solution for you.