Common Computer Issues: Error Messages During Boot

Dealing with error messages during boot can be a frustrating experience, especially when you rely on your computer for daily tasks. These issues can stem from a variety of sources, including hardware malfunctions, software conflicts, and corrupted system files. Understanding the root causes and learning how to troubleshoot these problems can save you time and potentially expensive repair costs. In this comprehensive guide, we will explore common boot error messages, their causes, and effective solutions to get your PC up and running smoothly again.

Understanding Error Messages During Boot

Understanding Error Messages During Boot

What Are Boot Error Messages?

Boot error messages are alerts that appear during the startup process of your computer, indicating a problem that prevents the operating system from loading correctly. These messages can vary significantly depending on the operating system and the nature of the issue. Common boot errors can range from simple misconfigurations to critical system failures that require immediate attention.

Why Do Boot Error Messages Occur?

Several factors can cause boot error messages, including:

  • Hardware Issues: Faulty hardware components such as hard drives, memory (RAM), and motherboards can prevent your computer from booting properly.
  • Software Conflicts: Incompatible or corrupted software can interfere with the boot process, leading to error messages.
  • Corrupted System Files: Essential system files may become corrupted due to malware, improper shutdowns, or failed updates, causing boot errors.

Types of Boot Error Messages

Types of Boot Error Messages

BIOS Error Messages

BIOS (Basic Input/Output System) is the firmware used to perform hardware initialization during the booting process. It provides runtime services for operating systems and programs. If there’s a problem at this stage, the BIOS will display error messages to help diagnose the issue.

Common BIOS Error Messages and Their Meanings

  1. CMOS Checksum Error: Indicates a problem with the BIOS settings. This can be caused by a dead CMOS battery, which maintains the BIOS settings when the computer is turned off. Replacing the battery often resolves this issue.
  2. No Boot Device Found: This error occurs when the BIOS cannot find a device to boot from. This can be due to incorrect boot order settings, a disconnected or faulty hard drive, or a damaged boot sector.
  3. Keyboard Not Detected: This error appears when the BIOS fails to detect a keyboard. It can be caused by a disconnected or faulty keyboard or a problem with the keyboard port.

Windows Boot Error Messages

Windows operating systems have specific boot error messages that can occur during startup. These messages often provide clues about the underlying issue.

Common Windows Boot Error Messages

  1. Blue Screen of Death (BSOD): This is a critical error screen displayed by Windows when the system encounters a fatal error. Common causes include hardware failures, driver issues, and software conflicts.
  2. Bootmgr is Missing: This error indicates that the Boot Manager, a critical component for booting Windows, is missing or corrupted. It can often be fixed by repairing the boot sector using Windows installation media.
  3. NTLDR is Missing: Similar to the Bootmgr error, this indicates a problem with the NT Loader. It’s common in older versions of Windows and can usually be resolved by restoring the NTLDR file from the Windows installation media.

Mac Boot Error Messages

Mac computers also have their own set of boot error messages, which can be quite different from those on Windows PCs.

Common Mac Boot Error Messages

  1. Question Mark Folder: This error indicates that the Mac cannot find a valid operating system to boot from. It can be caused by a missing or corrupted system folder, or a failed hard drive.
  2. Prohibitory Symbol: This symbol appears when the system detects a hardware or software issue that prevents the Mac from booting. It can be due to incompatible macOS versions, corrupted system files, or hardware failures.
  3. Spinning Globe: This symbol indicates that the Mac is trying to start from the internet recovery mode. It usually appears when there is an issue with the local recovery partition.

Diagnosing Boot Error Messages

Diagnosing Boot Error Messages

Initial Troubleshooting Steps

When you encounter boot error messages, it’s essential to start with some basic troubleshooting steps to identify and resolve the issue. Here are a few initial steps you can take:

  1. Check Hardware Connections:
  • Ensure all cables are securely connected.
  • Verify that all internal components, such as the hard drive, RAM, and graphics card, are properly seated.
  • Disconnect any external devices (USB drives, printers, external hard drives) that might interfere with the boot process.
  1. Reset BIOS Settings:
  • Enter the BIOS setup utility (usually by pressing a key like F2, F10, or DEL during startup).
  • Restore default settings, often labeled as “Load Setup Defaults” or similar.
  1. Test with Minimal Hardware Configuration:
  • Remove all non-essential hardware components (e.g., additional RAM sticks, extra hard drives).
  • Boot the system with the bare minimum required hardware to see if the issue persists.

Using Diagnostic Tools

Diagnostic tools can help identify the root cause of boot error messages. Both Windows and Mac systems have built-in tools, and there are also third-party options available.

Built-in Diagnostic Tools for Windows

  1. Windows Memory Diagnostic:
  • Useful for checking RAM issues.
  • Can be accessed by typing “Windows Memory Diagnostic” in the search bar and selecting the tool.
  • Follow the prompts to restart the computer and run the diagnostic.
  1. CHKDSK (Check Disk):
  • Helps detect and repair file system errors and bad sectors on the hard drive.
  • Open Command Prompt as an administrator and type `chkdsk /f /r`, then press Enter.
  1. Windows Startup Repair:
  • Automatically scans and fixes problems that prevent Windows from starting.
  • Can be accessed by booting from Windows installation media and selecting “Repair your computer.”

Built-in Diagnostic Tools for Mac

  1. Apple Diagnostics:
  • Checks for hardware issues.
  • To use, shut down the Mac, then turn it on and immediately press and hold the D key.
  1. Disk Utility
  • Helps repair disk permissions and file system errors.
  • Accessed from macOS Recovery by pressing Command + R during startup, then selecting Disk Utility from the menu.
  1. Safe Mode:
  • Starts the Mac with only essential system extensions and checks the startup disk.
  • Can be accessed by holding the Shift key during startup.

Third-Party Diagnostic Software

  1. MemTest86:
  • Comprehensive RAM testing tool.
  • Can be downloaded and run from a bootable USB drive.
  1. SeaTools:
  • Developed by Seagate, useful for diagnosing and repairing hard drive issues.
  • Available for both Windows and Mac.

Understanding Error Codes

Interpreting error codes displayed during the boot process is crucial for diagnosing the issue. Here are some tips and resources for understanding these codes:

  1. Refer to the Manufacturer’s Documentation:

   – Most BIOS and system manufacturers provide detailed documentation that explains error codes and their meanings.

  1. Online Resources:

   – Websites like Tom’s Hardware and forums such as Reddit and Stack Exchange have extensive user-contributed solutions and explanations for various error codes.

  1. Error Code Databases:

   – Comprehensive databases, such as Microsoft’s and Apple’s support pages, list common error codes and troubleshooting steps.

Fixing Common Boot Error Messages

Fixing Common Boot Error Messages

Resolving BIOS Errors

BIOS errors can often be resolved through a series of troubleshooting steps. Here’s how to fix some common BIOS errors:

CMOS Checksum Error

  1. Replace the CMOS Battery:
  • Shut down the computer and unplug it from the power source.
  • Open the computer case and locate the CMOS battery on the motherboard.
  • Carefully remove the old battery and replace it with a new one (usually a CR2032 battery).
  • Reboot the computer and enter the BIOS to reset the date and time if necessary.
  1. Reset BIOS Settings:
  • Enter the BIOS setup utility during startup (typically by pressing a key such as F2, F10, or DEL).
  • Look for an option to load the default settings, often labeled as “Load Setup Defaults” or “Reset to Default.”
  • Save and exit the BIOS.

No Boot Device Found

  1. Check Boot Order:
  • Enter the BIOS setup utility and navigate to the Boot menu.
  • Ensure that the correct hard drive or SSD is selected as the primary boot device.
  • Adjust the boot order if necessary, then save and exit.
  1. Inspect Hard Drive Connections:
  • Power off the computer and open the case.
  • Check that the hard drive’s power and data cables are securely connected.
  • If possible, try using different cables or connecting the hard drive to another SATA port.
  1. Run a Disk Check:
  • If the hard drive is detected but not booting, connect it to another computer and run a disk check using tools like CHKDSK or a third-party disk utility.

Keyboard Not Detected

  1. Reconnect the Keyboard:
  • Ensure that the keyboard is securely plugged into the correct port (USB or PS/2).
  • Try connecting the keyboard to a different USB port.
  1. Test with Another Keyboard:
  • Borrow or use another keyboard to determine if the issue is with the keyboard itself or the computer’s port.
  1. Update BIOS:
  • Check the motherboard manufacturer’s website for BIOS updates that may resolve compatibility issues with newer keyboards.

Fixing Windows Boot Errors

Blue Screen of Death (BSOD)

  1. Analyze the Error Code:
  • Take note of the error code displayed on the BSOD screen.
  • Use online resources or Microsoft’s support pages to identify the cause of the error code.
  1. Check for Driver Issues:
  • Boot into Safe Mode by pressing F8 during startup and selecting Safe Mode with Networking.
  • Open Device Manager and look for any devices with a yellow exclamation mark.
  • Update or roll back drivers as necessary.
  1. Run System File Checker (SFC):
  • Open Command Prompt as an administrator and type `sfc /scannow`, then press Enter.
  • Allow the system to scan and repair any corrupted system files.

Bootmgr is Missing

  1. Use Windows Installation Media:
  • Boot from the Windows installation media (USB or DVD).
  • Select “Repair your computer” and navigate to Troubleshoot > Advanced options > Command Prompt.
  • Type `bootrec /fixmbr` and `bootrec /fixboot`, then press Enter after each command.
  1. Rebuild the BCD (Boot Configuration Data):
  • In the Command Prompt, type `bootrec /rebuildbcd` and press Enter.
  • Follow the prompts to add the installation to the boot list.

NTLDR is Missing

  1. Copy the NTLDR and NTDETECT.COM Files:
  • Boot from the Windows installation media and open Command Prompt.
  • Copy the NTLDR and NTDETECT.COM files from the installation media to the root of the C: drive using the following commands:


     copy D:\i386\ntldr C:\

     copy D:\i386\ C:\


     Replace `D:` with the drive letter of your installation media.

  1. Check Boot Configuration:
  • Ensure that the boot configuration is correct by running `bootcfg /rebuild` in the Command Prompt.

Fixing Mac Boot Errors

Question Mark Folder

  1. Reset NVRAM (Non-Volatile Random-Access Memory):
  • Shut down the Mac, then turn it on and immediately press and hold Option + Command + P + R.
  • Hold the keys for about 20 seconds, then release them and let the Mac restart.
  1. Use macOS Recovery:
  • Restart the Mac and hold Command + R to boot into macOS Recovery.
  • Select Disk Utility, choose your startup disk, and click “First Aid” to check and repair any disk issues.
  1. Reinstall macOS:
  • In macOS Recovery, select “Reinstall macOS” to install a fresh copy of the operating system.

Prohibitory Symbol

  1. Check for Incompatible macOS Version:
  • Ensure that your Mac is compatible with the installed macOS version.
  • Boot into macOS Recovery and reinstall a compatible version if necessary.
  1. Repair Disk:
  • Use Disk Utility in macOS Recovery to check and repair disk issues.
  1. Reinstall macOS:
  • If disk repair does not resolve the issue, reinstall macOS from macOS Recovery.

Spinning Globe

  1. Ensure Stable Internet Connection:

   – The spinning globe indicates internet recovery mode, so ensure your Mac is connected to a stable internet connection.

  1. Run Disk Utility:

   – In internet recovery mode, select Disk Utility and run “First Aid” to repair the disk.

  1. Reinstall macOS:

   – If the issue persists, use internet recovery to reinstall macOS.

How Safemode Computer Service Can Help Address the Issue

Safemode Computer Service Logo

Services Offered by Safemode Computer Service

When it comes to resolving boot error messages and other common computer issues, Safemode Computer Service offers a range of professional services to get your system back on track. Here’s how Safemode Computer Service can assist you:

  1. Comprehensive Diagnostics:

   – Safemode Computer Service employs advanced diagnostic tools to accurately identify the root cause of boot errors. Whether it’s a hardware malfunction, corrupted system files, or software conflicts, their experts can pinpoint the issue quickly and efficiently.

  1. BIOS and Firmware Updates:

   – Updating BIOS and firmware can resolve many boot-related issues. Safemode Computer Service ensures that your system’s firmware is up to date and correctly configured, reducing the likelihood of future boot problems.

  1. Hardware Repairs and Replacements:

   – If your boot errors are caused by faulty hardware components, Safemode Computer Service can repair or replace the necessary parts. From hard drives and RAM to motherboards and power supplies, their technicians are skilled in handling all types of hardware repairs.

  1. Operating System Reinstallation:

   – In cases where the operating system is severely corrupted, a complete reinstallation might be necessary. Safemode Computer Service can perform a clean installation of your operating system, ensuring that all drivers and updates are correctly installed and configured.

  1. Data Recovery and Backup Solutions:

   – Safemode Computer Service offers data recovery services to retrieve important files from damaged or corrupted drives. They also provide backup solutions to protect your data from future loss, ensuring that your valuable information is always secure.

  1. Preventive Maintenance:

   – Beyond immediate repairs, Safemode Computer Service provides preventive maintenance services to keep your system running smoothly. This includes regular check-ups, software updates, and cleaning to prevent dust buildup and overheating.

Why Choose Safemode Computer Service?

Choosing Safemode Computer Service for your computer repair needs ensures that you receive:

  • Expert Technicians: Skilled professionals with extensive experience in diagnosing and repairing a wide range of computer issues.
  • Quality Parts: High-quality replacement parts that ensure long-lasting repairs.
  • Customer Satisfaction: A commitment to customer satisfaction, ensuring that you receive the best service possible.
  • Fast Turnaround: Efficient service with quick turnaround times, so you can get back to your routine without prolonged disruptions.
  • Comprehensive Support: Ongoing support and maintenance to prevent future issues and keep your system running smoothly.


Dealing with common computer issues like error messages during boot can be a daunting task, but understanding the causes and solutions can make the process much more manageable. Whether you’re encountering BIOS errors, Windows boot issues, or Mac startup problems, having a clear troubleshooting guide can help you identify and resolve these issues efficiently.

By following the steps outlined in this comprehensive guide, you can address many common boot errors yourself, from checking hardware connections to using diagnostic tools and performing system repairs. Regular maintenance practices, such as keeping your software and drivers up to date, running antivirus scans, and performing regular backups, are crucial in preventing these issues from occurring in the first place.

However, not all problems can be fixed at home. When faced with persistent or complex issues, professional help may be necessary. Safemode Computer Service offers expert diagnostics, repairs, and preventive maintenance to ensure your computer runs smoothly and efficiently. Their experienced technicians can handle a wide range of issues, providing you with peace of mind and reliable solutions.

Remember, a proactive approach to computer maintenance can save you time, money, and frustration in the long run. By keeping your system in good health, you can enjoy a seamless and efficient computing experience.

Call to Action

If you’ve experienced any of these common computer issues or have any other computer-related concerns, don’t hesitate to reach out to Safemode Computer Service for professional assistance. Share your experiences or questions in the comments below, and check out our related posts for more tips on maintaining and troubleshooting your computer. Contact Safemode Computer Service today to ensure your computer is always in top condition.