Messing with Windows system files can be disastrous. If you do, you may not be able to log in again, or the system may fail to boot the next time when you turn it ON.

What’s worse is that it can lead to system and application crash that can damage or corrupt your system drive—making the drive and data inaccessible.

In this guide, you will learn about the 7 most critical and vulnerable Windows files and folders. Also, why you should never touch them!

1. Windows Folder

Every file in the Windows folder located at C:Windows is critical for the Windows operating system (OS) and other applications installed on your PC to function properly. Any modification or deletion inside the Windows folder, including file movement, can cause your system to malfunction and crash. And you may not be able to boot and access your system without repairing or reinstalling Windows OS.

2. System32 Folder

System32 is a subfolder located at C:WindowsSystem32. System32 is a critical subfolder of the Windows Operating System that contains a vital Windows system and default program files.

It contains the Dynamic Link Library (DLL) files which are shared library files used by both Windows system software and third-party applications to perform various tasks and operations.

The folder also contains Windows Registry files and the ‘Drivers’ folder that contains device driver files required by the Windows OS to communicate with the system hardware.

If you delete the System32 folder or any file from it, your Windows system may not boot and may get damaged beyond repair.

3. WinSxS Folder

Similar to System32, WinSxS is another critical and sensitive folder located under ‘C:Windows directory.

WinSxS means Windows Side-by-Side.

WinSxS stores different copies of the system and DLL files. This particular folder may grow to several gigabytes, and it is normal as it stores components of new Windows updates and previous Windows versions for a certain period and allows you to roll back to previous versions, if necessary.

A common question related to WinSxS is, ‘Can we delete the WinSxS folder to increase disk space?’

The answer is—you should not. Deleting the WinSxS folder or files is easy, but it may severely damage your Windows. Your PC may fail to boot and install updates.

But if you need to reduce the size of WinSxS and regain disk storage space, use the Disk Cleanup tool.

4. Program Files Folder

C:Program Files and C:Program Files(x86) are two critical folders that contain all the application files installed on your Windows PC. These folders are the default location where all 64-bit and 32-bit(x86) software are installed.

You should never try deleting the ‘Program Files’ folder or contained files directly. If you need to uninstall a program or software, use Control Panel.

In case you delete this folder or its subfolders and files, you may not be able to use your system and apps properly. It may also lead to problems such as application crash and abrupt system crash or shutdown.

5. System Volume Information

In the Windows system, the default location of System Volume Information is C:. But you will find the System Volume Information folder even on an external USB drive and other partitions of your hard drive. By default, it’s a hidden and protected folder.

The size of this folder may also grow larger with time. But even if you manage to delete this folder, you shouldn’t. It contains important system data which also includes system restore points.

If storage space used by the System Volume Information folder is the issue, you can manage it by reducing the allocated space to System Restore in Windows.

6. Page File.sys

Pagefile.sys is the “paging file” that Windows uses for memory (RAM) management. Located under C: root directory, it’s Windows’ virtual memory, which is used when the physical RAM gets full. And this file can be easily deleted.

But deleting Pagefile.sys from your PC will cause performance issues including system freeze causing you to force shutdown system. This can further cause drive errors and damage system files.

If the Pagefile.sys size is causing you trouble, reduce it from ‘Advanced system settings’ under Control Panel.

7. Swapfile.sys

Similar to Pagefile.sys, the Swapfile.sys helps in system performance. You can delete the Swapfile.sys file quickly, just like any other file, with admin access.

But removing this lightweight file, usually less than 256 MB, is not recommended as it won’t save you much space but would lead to performance issues on your Windows PC.

Also, the file is related to the main page file—disabling Pagefile.sys also disables Swapfile.sys.

What If you accidentally delete a Critical File or Folder in Windows

Accidental deletion due to human errors is more common than virus or malware infection. But if you have accidentally deleted a critical file or folder from your Windows PC or supported storage media, stop using your system or affected media storage immediately and check the Recycle Bin.

If deleted files and folders aren’t found in the Recycle Bin, check your backups and restore them.

However, at times, when a backup isn’t available or turn out to be obsolete, you can use a DIY data recovery software such as Stellar Data Recovery Premium or Recuva to quickly restore deleted files and folders in a Windows PC.

Do check: Forgot Windows 10 Password – How to Recover?

Also read: Top 8 Powerful Tools for Finding Duplicate Images in Windows PC

Conclusion

Unlike Linux and UNIX based operating systems such as Ubuntu and macOS, Windows system files are easily accessible and prone to accidental deletion. This blog shared information on the seven most critical Windows files and folders that you should never touch.

These critical system files play an important role in running the OS and programs and are an essential part of the Windows operating system. Deleting these critical files does not only damage your system but can also harm other system components including the system hardware. Doing this may further cause performance issues, boot failure, system crashes, and permanent data loss situations.

But if you have accidentally deleted a critical file or folder in Windows or external media storage, check Recycle Bin or use the backup to restore. If files are not found in the Recycle Bin or backup, use a DIY data recovery software to get back files immediately.

And to avoid a data loss situation, always keep a regular backup.