THE LOCAL DISK FOLDER (C:\)
Although we dived straight into the Windows folder on page 51, its parent folder for your C: drive also has some mysterious junk, alongside essential system files. Here’s how to deal with these items
Perflogs
The Perflogs folder stores log files containing information about your operating system’s performance. It’s mainly used by the Performance Monitor tool in Windows 10 and 11, which you can access by typing perfmon into the search box then selecting Open.
When you try to open the Perflogs folder, Windows will warn that you don’t currently have permission to access it, which you can simply bypass by clicking Continue. This makes the folder sound dangerous to mess with, but it’s usually empty and can be deleted through File Explorer without requiring confirmation. Even if it does contain log files, these are only for reference and removing them won’t affect your PC’S performance.
However, Windows will automatically regenerate the Perflogs folder after you restart your computer, so deleting it is pointless. To hide it instead, right-click the folder, choose Properties and tick the Hidden box (see screenshot below), then click OK. You’ll still see it if you have File Explorer or your alternative file manager set to show hidden items.
Hiberfil.sys
Another big space hog in the Windows folder is the ‘hiberfile.sys’ file, which controls the Hibernate feature. This helps Free up space from the hidden ‘hiberfile.sys’ file by disabling the Hibernate feature conserve power when you’re not using your PC, by copying data from your system’s memory then powering down your computer. When you turn it back on, Windows loads all the saved data from the ‘hiberfile.sys’ file
Hiberfil.sys can only be seen in the C: folder when you show hidden files in File Explorer and untick the option to ‘Hide protected operating system files’ on the View tab of File Explorer Options. To access this, type folder options into the Windows search box and click Open.
Nevertheless, it can take up several gigabytes of space and you don’t need it if you never set your PC to hibernate, rather than ‘sleep’, or if your main drive is an SSD. Because SSDS use less power than standard hard drives, they don’t require hibernation, and copying data to the ‘hiberfil.sys’ file simply wastes storage and slows things down.
You can’t delete the ‘hiberfil.sys’ file, but instead need to disable the feature. This will free up valuable storage used by Hibernate and let you re-enable it if you change your mind later.
Type cmd into the Windows search box and choose ‘Run as administrator’. When Command Prompt opens, type the following command and press Enter: powercfg /h off ( 1 in our screenshot above). You won’t receive confirmation that Hibernate is disabled, but you can check by typing powercfg /a and pressing Enter – this should say that ‘Hibernation has not been enabled’ 2 . Turn ‘Hibernate’ back on again by entering the command powercfg /h on.
Windows.old
If you recently upgraded to Windows 11, you may have a massive folder in your local drive folder called ‘Windows.old’. This allows you to roll back to Windows 10 for up to 10 days after you upgraded, Safely delete the folder containing your previous installation of Windows after which it should be automatically removed. If the folder doesn’t disappear, and you’re happy with Windows 11, you can delete it yourself.
The safest way to do this is to open Settings, click System followed by Storage, then choose ‘Clean-up recommendations’. Select ‘Previous Windows installations’
( 1 in our screenshot above) and click the ‘Clean up [file size]’ button 2.
WHAT NOT TO DELETE FROM THE LOCAL DISK FOLDER Pagefile.sys
After you tweak File Explorer to show hidden and protected system files, you’ll see a file called ‘pagefile.sys’, which is probably one of the largest on your hard drive. This is the page or paging file, which Windows uses to extend your PC’S RAM when it starts running low on physical memory, a process known as switching to virtual memory.
The page file is therefore essential to system performance, because without it your PC would have nowhere to offload excess data, causing it to freeze and crash. But the size of the file – 7.3GB on our Windows 10 PC – makes it seem like a greedy space hog.
Although it’s possible to delete the page file (though not through File Explorer), it’s much safer to reduce its maximum size. To do this, open the Settings app in Windows 10 or 11, choose System, then About and click ‘Advanced system settings’. Click the Advanced tab, then the Settings button under Performance and click the Advanced tab there. Click ‘Change’ under ‘Virtual memory’ and untick ‘Automatically manage paging file size for all drives’.
Select ‘Custom size’ ( 1 in our screenshot top of page 55) and type 400 in the ‘Initial size’ box and 2000 in ‘Maximum size’ 2 . That limits virtual
memory to 2GB, which is big enough to keep your PC running smoothly but small enough not to hog your hard drive. Click ‘Set’ 3 then OK and restart your PC.
If you’re prepared to risk deleting your whole page file, select ‘No paging file’ instead, but because this will leave your PC with no virtual memory, we strongly advise against it. This will also remove the file ‘swapfile.sys’ from your local drive folder. You can restore ‘pagefile.sys’ to its default settings by re-enabling the ‘Automatically manage’ option.
System Volume Information
Showing protected system files will also reveal the System Volume Information folder, but you won’t be able to open it, even with administrator permissions.
This is where Windows keeps your system restore points as well as other system data you shouldn’t tamper with, though the folder can be forcibly deleted using third-party tools.
A better idea is to free up space from old system restore points using the Disk Clean-up tool in Windows 10 and 11. Type disk cleanup into the search box, press Enter to launch the tool and click ‘Clean up system files’. Click the More Options tab, then the ‘Clean up’ button under ‘System Restore and Shadow Copies’ (see screenshot below) to remove all but the most recent restore point.
If you prefer to keep multiple restore points, in case of disaster, you can reduce how much storage is allocated to them. Type system restore into the Windows search box, press Enter and click the System Protection tab. Next, click the
Configure button and drag the Max Usage slider to the left to devote less space to restore points. Windows will automatically delete older restore points to make room for new ones.
Program Files
Most PCS now run 64bit Windows, which means you’ll see two Program Files folders in your C: local drive folder. The one called Program Files stores the files for the 64bit software you’ve installed on your PC, while the ‘Program Files (x86)’ folder is where you’ll find your 32bit software.
It’s tempting to remove unwanted programs, especially large and rarely used ones, directly from this folder by selecting or right-clicking them and choosing Delete. Unless the software is currently running, Windows will remove its folder and all the files within it, and either send them to the Recycle Bin or permanently delete them.
However, because programs you install make changes to the Windows registry and add files to other folders on your PC, removing them in this way won’t properly uninstall them. Instead, it risks causing performance problems and errors, because Windows will try to use software that’s no longer fully installed.
For this reason, you should always uninstall programs using their own uninstallers, reliable third-party tools such as BC Uninstaller (www.bcuninstaller.com) or the Windows Settings app.
In the latter, click ‘Apps’ then ‘Apps & features’ (in Windows 10) or ‘Installed apps’ (in Windows 11), select a program and click Uninstall (see screenshot above). This will cleanly remove the software and its ‘related info’, though if any folders remain after you restart your PC, you can manually delete those.