tree size and file explorer showing different used space

Question

how did i notice?

my dirive allocated space is about 176.44gb

when i was trying to free space i opened tree size to see what was going on i notice that it said i had 121.34gb used(so about 55.1gb free)

but when i opened file explorer it said i have 61.1 gb free so the difference is about 6 gb

but when i opened cmd and typed this command 'fsutil volume diskfree C:' it showed i had the same as file explorer but it showed i had 5 gb reserved and that is almost the difference but the rest of the diff is coming from windows folder on treesize it shows it's 28.47gb but in file explorer 27.1gb so this is the other 1gb

so how can i fix this and how can i make either tree size or windows explorer show the true size

attachments

i can't upload the photos it gives me error idk why

so here is an imgur link

https://imgur.com/a/1XCoqhS

i can now upload photos

Answer 1

Hello ,  adam ossama Welcome to Microsoft Community. Based on your description, the discrepancy between the used space and available space shown by TreeSize and File Explorer (as well as the fsutil command) is a very common and normal technical phenomenon. This is typically not an issue that requires "fixing," but rather stems from the different ways these tools measure and report disk space.

Here are some key points you mentioned:

TreeSize vs. File Explorer/fsutil (approximately 6GB difference):

You discovered about 5GB of "Reserved Space" using the fsutil volume diskfree C: command, which is likely the main cause of the discrepancy.

What is Reserved Space? The Windows file system (NTFS) reserves a portion of disk space for certain critical system functions. This space physically exists on the disk but is not directly used for storing user files, or its usage may not be fully accounted for by file scanning tools like TreeSize. These reserved spaces typically include:

• Master File Table (MFT) Reserved Space: The MFT itself and the reserved area needed for its growth.
• Shadow Copies: Used for system restore points and file history. Even if you haven't actively created restore points, the system may automatically create them.
• Other Metadata and Logs: Log files and other management structures required for the file system to operate.

Tool Differences:

• TreeSize: Primarily scans files and folders on the disk and sums their actual size or occupied space to calculate used space. It may not fully access or account for the aforementioned system reserved areas, or its calculation method may not include this "overhead."
• File Explorer/fsutil: These tools report statistics based on the file system volume level. The "used space" they see is closer to the overall volume occupancy, including user files, system files, and the various system overheads and reserved spaces mentioned above. fsutil more explicitly points out this reserved space. Therefore, the "available space" shown by File Explorer usually more accurately reflects the space you can actually use to store new files.

Windows Folder Size Difference (approximately 1.37GB):

This discrepancy is also quite common and may be due to:

• Permissions: If TreeSize runs with administrator privileges, it may scan system-protected files or folders that File Explorer under normal user permissions cannot fully access or calculate the size of.
• Hidden Files and System Files: The settings for whether to include all hidden files and protected operating system files in the statistics may differ between the two.
• Hard Links/Junctions: Windows folders (especially the WinSxS folder) extensively use links. Different tools may calculate the actual file size pointed to by these links differently, leading to statistical discrepancies. TreeSize may be more inclined to calculate the actual file size pointed to by the links, while File Explorer properties may only calculate the link itself or handle it differently.
• Calculation Precision and Method: When calculating a very large number of small files, the cumulative effect of minor differences in calculation methods (such as "size" vs. "size on disk") can also lead to differences.

Which is the "real" size? It depends on what we want to understand:

• If you want to know which specific files and folders are taking up a lot of space for cleanup purposes, TreeSize is a very good tool. It excels at visualizing the size distribution of files/folders.
• If you want to know how much space is left on the drive to write new data, the information provided by File Explorer or fsutil is closer to "available" space because it considers the overall occupancy and reservations at the file system level.

This is not an error, so there is no standard "fix" method. You need to understand that different tools provide different dimensions of information.

I hope this explanation helps you understand the situation!

Best wishesLeo.Z | Microsoft Community Support Specialist