Windows 10 includes a built-in power-saving feature called Hibernation. When you put your computer into hibernation mode, Windows saves the current state of your system, including open applications, documents, and settings, into a special file called Hiberfil.sys. This file is stored on the system drive, usually the C: drive, and allows Windows to restore your previous session quickly when the computer is powered on again.
Although hibernation is useful, the Hiberfil.sys file can consume a significant amount of disk space. On computers with large amounts of RAM, the file may occupy several gigabytes of storage. Users who have limited SSD space often look for ways to reduce the size of the hibernation file without completely disabling the feature. Fortunately, Windows 10 provides built-in tools that allow you to shrink the Hiberfil.sys file while keeping essential hibernation functionality available.
In this guide, you will learn what Hiberfil.sys is, why it becomes large, and the different methods you can use to reduce its size safely in Windows 10.
What Is Hiberfil.sys In Windows 10?
The Hiberfil.sys file is a hidden system file created automatically by Windows whenever hibernation is enabled. Its primary purpose is to store the contents of system memory when the computer enters hibernation mode. When you resume the system, Windows reads the information from the file and restores your session exactly as it was before shutdown.
The size of Hiberfil.sys depends largely on the amount of RAM installed in the computer. For example, a system with 16 GB of RAM may have a hibernation file that consumes several gigabytes of storage space. Since SSD storage can be expensive and limited, many users prefer reducing the file size instead of leaving it at the default setting.
Windows supports two hibernation modes:
- Full Hibernation
- Reduced Hibernation
The reduced mode requires less disk space and is sufficient for features such as Fast Startup, making it an excellent option for users who want to save storage.
Method 1: Check The Current Size Of Hiberfil.sys
Before reducing the file size, it is helpful to determine how much storage the file currently occupies. Since the file is hidden and protected by Windows, you must enable hidden file viewing first.
Follow these steps:
- Open File Explorer.
- Click the View tab.
- Select Options and choose Change folder and search options.
- Open the View tab.
- Enable Show hidden files, folders, and drives.
- Uncheck Hide protected operating system files.
- Click Apply and OK.
- Open the C: drive.
You should now see the Hiberfil.sys file in the root of the drive. Right-click the file and select Properties to view its size.
Checking the current size provides a useful reference point so you can verify the storage savings after applying optimization methods.
Method 2: Reduce Hiberfil.sys Size Using Command Prompt
The easiest and most effective method for reducing the hibernation file size is through the Powercfg command. Windows allows administrators to specify a percentage value that determines how much disk space the Hiberfil.sys file should occupy.
Follow these steps carefully:
- Press Windows + S.
- Type Command Prompt.
- Select Run as administrator.
- Click Yes when prompted by User Account Control.
- Enter the following command:
powercfg /h /size 50- Press Enter.
The number represents the percentage of installed RAM allocated to the hibernation file. The minimum supported value is generally 40 percent, while larger values provide additional storage capacity for full hibernation functionality.
For example:
powercfg /h /size 40This command attempts to reduce the Hiberfil.sys file to approximately 40 percent of installed memory. After executing the command successfully, Windows immediately resizes the file.
You can reopen the file properties afterward to verify the reduction in disk usage.
Method 3: Switch To Reduced Hibernation Mode
Windows 10 offers a reduced hibernation mode that significantly decreases the size of Hiberfil.sys. This mode is particularly useful for users who mainly rely on Fast Startup rather than traditional hibernation.
To enable reduced mode:
- Open Command Prompt as Administrator.
- Type the following command:
powercfg /h /type reduced- Press Enter.
Once enabled, Windows automatically shrinks the hibernation file and uses less storage space. Reduced mode supports Fast Startup while requiring considerably less disk space than full hibernation mode.
Many users find this option to be the best balance between maintaining fast boot performance and conserving valuable SSD storage.
If you later need complete hibernation functionality again, you can restore full mode using:
powercfg /h /type fullAfter running the command, Windows expands the hibernation file to support complete system memory storage during hibernation.
Method 4: Disable And Re-Enable Hibernation
Sometimes the Hiberfil.sys file becomes larger than expected or does not resize correctly. Disabling and then re-enabling hibernation can force Windows to recreate the file with optimized settings.
Follow these steps:
- Open Command Prompt as Administrator.
- Enter the following command:
powercfg /h off- Press Enter.
- Restart the computer.
- Open Command Prompt again as Administrator.
- Enter:
powercfg /h on- Press Enter.
Windows creates a fresh Hiberfil.sys file during the reactivation process. In some situations, this results in improved storage efficiency and resolves file corruption issues.
Keep in mind that disabling hibernation temporarily removes Fast Startup and hibernation functionality until the feature is enabled again.
Method 5: Disable Hibernation Completely To Recover Maximum Space
If you never use hibernation and do not need Fast Startup, disabling hibernation entirely will remove the Hiberfil.sys file and reclaim all associated storage space.
To disable hibernation:
- Open Command Prompt as Administrator.
- Run:
powercfg /h off- Press Enter.
Windows immediately deletes the Hiberfil.sys file and frees the disk space occupied by it.
This option can recover several gigabytes of storage on systems equipped with large amounts of RAM. For example, computers with 16 GB, 32 GB, or more memory may gain substantial free space after disabling hibernation.
If you later decide to restore the feature, simply run:
powercfg /h onThe system recreates the Hiberfil.sys file automatically.
How Much Space Can You Save?
The exact amount of storage savings depends on the amount of installed RAM and the selected hibernation configuration.
Typical examples include:
- 8 GB RAM system: approximately 3–6 GB savings
- 16 GB RAM system: approximately 6–12 GB savings
- 32 GB RAM system: approximately 12–24 GB savings
- 64 GB RAM system: potentially over 25 GB savings
Users with SSDs often notice the greatest benefits because every gigabyte of free space contributes to improved performance and storage flexibility.
Reduced hibernation mode generally offers the best compromise between storage conservation and maintaining Windows Fast Startup functionality.
Is It Safe To Reduce Hiberfil.sys Size?
Yes, reducing the size of Hiberfil.sys is generally safe when using Microsoft’s built-in Powercfg commands. Windows automatically ensures that the file remains large enough to support the selected hibernation mode.
However, users should avoid manually deleting the file through File Explorer because it is a protected system file managed by Windows. Improper deletion attempts can lead to system errors or incomplete hibernation functionality.
Using official Powercfg commands is the recommended and safest approach.
Frequently Asked Questions
Why is Hiberfil.sys so large?
The file stores memory information required for hibernation. Systems with more RAM require larger Hiberfil.sys files because Windows must save additional data before shutting down.
Can I delete Hiberfil.sys manually?
No. The recommended method is disabling hibernation using the Powercfg command. Windows will then remove the file automatically and safely.
Will reducing Hiberfil.sys affect performance?
Reducing the file size generally does not affect everyday computer performance. However, using an excessively small size may limit full hibernation capabilities.
Does Fast Startup require Hiberfil.sys?
Yes. Windows Fast Startup relies on a hibernation file. If hibernation is disabled completely, Fast Startup will also be disabled.
What is the minimum Hiberfil.sys size allowed?
Windows typically allows the file size to be reduced to approximately 40 percent of installed RAM, although exact limits can vary between versions.
Can I restore the original file size later?
Yes. You can switch back to full hibernation mode or specify a larger percentage using Powercfg commands whenever needed.
Final Thoughts
The Hiberfil.sys file is an important part of Windows 10’s hibernation and Fast Startup features, but it can occupy a significant amount of valuable disk space, especially on systems equipped with large amounts of RAM. Fortunately, Windows provides several safe and effective methods to reduce the file size without sacrificing important functionality.
For most users, switching to reduced hibernation mode or adjusting the hibernation file percentage through the Powercfg command offers the best balance between storage savings and convenience. These methods preserve Fast Startup while freeing valuable SSD space that can be used for applications, games, or personal files. Users who never use hibernation can reclaim even more space by disabling the feature completely.
Regularly monitoring system storage and optimizing large system files can help maintain a healthy and efficient Windows installation. By following the methods described in this guide, you can safely reduce the size of Hiberfil.sys and make better use of your available disk space in Windows 10.
