Is your C drive full? Turn off this feature to easily free up 10GB!
Is Your C Drive Full? Turn Off This Feature and Free Up 10GB Instantly!
A “red C drive” is a headache for many people. When you see that C drive glowing red in File Explorer, it’s easy to feel helpless—unsure what to delete, what to keep, what can be moved, and what will break if moved.
In fact, on many computers, there’s a massive file lurking in the C drive. Deleting it can free up a huge chunk of space and give your C drive a “second wind.”
hiberfile.sys
hiberfile.sys is the system’s hibernation file. If you don’t use the hibernation feature, this file is unnecessary. On my computer, this file takes up 6.32 GB. The size varies greatly between machines—some can have files as large as 20 GB.
So, by deleting this file, you can reclaim a significant amount of C drive space.
How to View hiberfile.sys?
You can’t see this large file directly in File Explorer. You’ll need to tweak some settings to reveal its “true form.”
First, this file resides in the root directory of the C drive and is hidden by default. Even if you enable “Show hidden files,” you might still not see it. That’s because the operating system is still hiding some critical system-level files from you.
To fix this, you need to change the File Explorer settings.
For Windows 10:
- Open File Explorer
- Click “File” in the top-left corner, then “Options”
- Click the “View” tab, and uncheck “Hide protected operating system files (Recommended)”
- Click “OK” all the way through
For Windows 11:
- Click the three dots “…” in File Explorer
- Click “Options”
- Click the “View” tab, and uncheck “Hide protected operating system files (Recommended)”
- Click “OK” all the way through
Now, all Windows operating system files will be fully visible to you.
You’ll see hiberfile.sys displayed in the root directory of the C drive.
How to Delete hiberfile.sys
You can’t simply delete hiberfile.sys directly. You need to disable the system’s hibernation feature first.
Here’s how to turn off hibernation:
- Press the Windows key + S to open search
- Type “cmd,” right-click on Command Prompt, and select “Run as administrator”
- In the black window that appears, type the following command:
1 | |
- Press Enter, then close the Command Prompt window
Now, open your C drive again, and you’ll see that hiberfile.sys has disappeared. Your C drive space has increased.
If you want to re-enable hibernation, open Command Prompt again and type:
1 | |
Then check the C drive root directory—hiberfile.sys will be back.
The Pros and Cons of Hibernation
When your computer hibernates, it’s completely powered off, similar to shutting down.
So why is hiberfile.sys so large? Because during hibernation, the computer saves all user sessions and system sessions into this file.
In other words, your entire current work state is “frozen” in this file. When you wake the computer from hibernation, it reads hiberfile.sys and loads it into memory, restoring your previous work state.
The “Fast Startup” feature introduced in Windows 10 also uses the hibernation file. The noticeable improvement in Windows 10’s boot speed is thanks to this file.
When Fast Startup is enabled, shutting down the computer saves only the system session to the hibernation file (not the user session). When you boot up again, the system reads the system session from the hibernation file and loads it into memory.
This means that a computer with Fast Startup enabled doesn’t truly “shut down”—it enters a kind of “deep hibernation.” If this state persists for a long time, the system never gets a proper restart, which can lead to system issues.
So, is there no way to perform a true “cold boot” from scratch without disabling hibernation?
Of course there is. Restarting your computer performs a cold boot from scratch. So, occasionally restarting your computer can help rejuvenate the system.
Summary:
- Enable hibernation: Uses C drive space, allows the system to hibernate, and speeds up both shutdown and startup.
- Disable hibernation: Frees up C drive space, prevents the system from hibernating, and slows down both shutdown and startup.