What happens when you remove the hard drive from a computer?

Quick Answer

Removing the hard drive from a computer will prevent the computer from being able to boot up into the operating system. Without the hard drive installed, the computer has no way to load the operating system files that are necessary to start up. Some key things that will happen when the hard drive is removed include:

• The computer will not be able to boot into the operating system (e.g. Windows, macOS, Linux)
• Error messages related to the missing hard drive may appear on bootup
• The BIOS/UEFI settings may show that no hard drive is detected
• Any data stored on the removed hard drive will not be accessible to the computer
• Installed programs and apps on the hard drive will not be usable
• You will not be able to install software or save files without a hard drive present

Overall, the hard drive contains the crucial system files and data necessary for the computer to start up and operate. Removing it prevents the computer from loading the operating system and accessing any of the user data or installed programs on that drive. The computer hardware may still power on, but without a hard drive it will be unusable for most practical purposes.

Hard Drive Basics

Before getting into what happens when you remove a hard drive, it helps to understand what the hard drive does in a computer system.

The hard drive serves a few key roles:

• Storage for the operating system – The hard drive contains the operating system files that are loaded when the computer boots up. This includes Windows, macOS, Linux, etc. Without the hard drive, these system files cannot be accessed.
• Storage for software/applications – Any software, applications, and programs installed on the computer are stored on the hard drive. This allows them to be accessed and opened when needed.
• User file storage – All personal user files like documents, photos, downloads, and media are stored on the hard drive for retrieval. The operating system handles accessing these files on the drive.
• Settings storage – Configuration settings, preferences, and other options are saved to the hard drive for that particular computer setup.

So in summary, the hard drive acts as the long-term storage center for the operating system, apps, and user data. Removing it takes away the computer’s ability to access any of this vital software or information.

Boot Process Without a Hard Drive

When a computer boots up, it follows a strict sequence of events known as the boot process. This includes:

1. BIOS or UEFI initialization – low-level hardware checks
2. Selecting a boot device – chooses storage with bootloader info
3. Bootloader execution – initial operating system files loaded
4. Operating system startup – remaining OS is fully loaded

A key step here is choosing a boot device – this is typically the hard drive. The bootloader code that starts the operating system execution sequence resides on the hard drive.

Without a hard drive installed, the computer will still power on and the BIOS/UEFI will still initialize. However, when it gets to the boot device selection part there will be no available boot drive found.

This will generate an error along the lines of:

“No bootable device found”

or

“No boot disk has been detected or the disk has failed”

The system cannot proceed to loading the OS without those critical boot files on a drive. The computer may either stay stuck at this error screen or could be configured to attempt booting from another device if available (e.g. USB drive, network boot, etc). But the main operating system on the removed hard drive cannot be started up.

Internal Hard Drive vs External

It’s important to clarify the difference between internal and external hard drives here:

• Internal hard drive – This is the primary disk inside your desktop or laptop that the operating system gets installed on. Removing this drive will directly prevent the OS from booting up.
• External hard drive – This is an additional, optional portable hard drive that plugs into your computer via USB, Thunderbolt, etc. The external drive provides supplemental storage but the operating system does not rely on it for booting up. Removing this drive alone will not affect the ability to start up the computer and access the main internal hard drive boot files.

So when we talk about removing “the” hard drive, we mean that primary internal system disk where Windows, macOS, Linux is installed and set as the boot drive. Taking it out causes boot problems, while removing just an external drive does not. They provide complementary, but distinct roles.

Potential Error Messages

When you power on a computer that is missing its internal hard drive, you’ll generally see one of several error messages related to the failed boot process. Some examples include:

Error code: 0xc000000e (Windows)

• Issue – The boot selection failed because no boot disk can be found.
• Cause – Hard drive containing Windows boot files is missing.
• Solution – Reattach hard drive or select new bootable drive.

Error code: 0xc000000f (Windows)

• Issue – Windows boot configuration data is missing or corrupt.
• Cause – Hard drive with bootloader information is removed.
• Solution – Reconnect hard drive or restore boot files from recovery media.

“No Boot Device Available” (BIOS/UEFI)

• Issue – BIOS/UEFI cannot find a bootable device.
• Cause – Internal hard drive containing OS and bootloader is not detected.
• Solution – Reinstall internal hard drive properly so it is recognized.

“Hard Drive Error” (Linux)

• Issue – Linux bootloader cannot load the operating system.
• Cause – Hard drive that holds the OS and boot files is removed.
• Solution – Reconnect the internal hard drive or change boot device.

The common theme is that without the primary hard drive present, the normal boot process is interrupted due to the missing operating system files. Reinstalling the internal hard drive that holds the OS should resolve the error and allow booting again.

Checking BIOS/UEFI Settings

In addition to error messages on startup, removing the hard drive will also be reflected in the BIOS or UEFI settings on the computer.

BIOS (Basic Input/Output System) and UEFI (Unified Extensible Firmware Interface) are low-level firmware that handles the initial hardware initialization on a computer.

Part of their functionality includes detecting storage drives installed in the system. When you take out the main hard drive, this change will be shown in the BIOS/UEFI settings:

• The hard drive will no longer be listed on the boot priority or boot menu.
• The hard drive’s model, size, etc will not show up in the storage info section.
• SATA, NVMe, or other drive connectors that the hard drive used will be empty/unoccupied.

For example, if you have a 500GB hard drive plugged into SATA port 1 normally, that drive information and port occupation will disappear from the BIOS/UEFI when you remove it physically.

This can help confirm the hard drive is no longer being detected and validated the reason for the unsuccessful boot.

Data Access and Software Usability

Beyond booting up the operating system, removing the hard drive has other effects related to data accessibility and software usability:

• Inability to access user files – All personal documents, photos, downloads, and other user files are stored on the hard drive. Taking it out removes the ability to open any of this data.
• Installed programs are unavailable – Apps and software installed on that computer depend on the hard drive to store their executable files and program data. Removing it makes these programs unusable.
• Saving data requires a drive – Without a hard drive, the computer has nowhere to write and save any new files or changes. A drive is required for permanent storage.
• System reset may be needed – If the hard drive is reinstalled later, booting issues may occur if the operating system or bootloader is still configured for the previous drive. A full system restore might be required.

In summary, the hard drive provides the centralized storage location for the whole computer system to operate properly. Eliminating it essentially removes any meaningful functionality beyond just powering on the hardware.

When the Hard Drive Contains Multiple Partitions

On many hard drives, there are separate disk partitions configured to hold different data:

• Partition C: contains Windows system files
• Partition D: contains data files
• Partition E: contains recovery or utility software

If this is the case, different partitions will see different effects when the physical hard drive is removed as a whole unit:

• Partition with the OS (usually C:) – Will directly cause boot failure as described previously, since the operating system files are missing.
• Data partitions (e.g. D:) – Any data on those partitions will not be accessible and cannot be opened while that physical disk is disconnected.
• Recovery partitions – Cannot be used while the disk is removed. But the OS partition missing would prevent booting already in most cases.

So even with multiple partitions, removing the entire physical hard drive makes all of them inaccessible and prevents booting since the main OS partition is gone from the system.

Impacts Based on Operating System

While the general effects are similar overall, the specific impacts of removing a hard drive can vary slightly depending on which operating system the computer uses:

Operating System	Effects When Removing Hard Drive
Windows	Critical boot files like winload.exe, bootmgr, BOOTMGR, ntldr, etc will be missing BOOTMGR error codes like 0xc000000e or 0xc000000f may occur Boot device selection will fail, Windows cannot start
macOS (Mac)	Files like boot.efi would be unavailable, prohibiting boot Question mark folder icon may appear indicating missing boot files Startup Manager would show no available bootable volumes
Linux	Bootloader files like /boot/grub/grub.cfg or initrd.img would be missing “Hard drive error” or “No bootable device” errors common OPENSUSE, Red Hat, Ubuntu etc distros would fail to load

But while the specific files and error messages vary between operating systems, the end result is the same – the OS fails to start and boots to an error screen instead. This highlights the vital role the hard drive plays in any computer environment.

Conclusion

In summary, removing the primary internal hard drive from a computer prevents booting into the installed operating system due to critical missing system files.

Common effects include boot errors, inability to access applications and user data, lack of hard drive detection in BIOS/UEFI, and the computer being unusable for practical purposes without an OS.

While the hardware may still receive power, the drive where Windows, macOS, Linux or other platforms are installed must be present for full system functionality. So when troubleshooting boot issues, reconnecting or replacing the hard drive is one of the first steps to get the computer operating correctly again.