Windows File Explorer Displays Incorrect Folder Sizes

Chang Min 60 Reputation points
2026-11-05T09:34:09.4866667+00:00

File Explorer reports inconsistent folder sizes when users inspect directories containing large numbers of files. How can I investigate access permissions, symbolic links, filesystem metadata, and storage reporting behavior?

Windows for business | Windows 365 Enterprise
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  1. AI answer

    2026-11-05T09:34:33.64+00:00

    Use a combination of visibility checks, permission analysis, and comparison tools:

    1. Show hidden and protected files first. In File Explorer, open the volume, then go to Tools > Folder Options > View. Enable Show Hidden Files and Folders and clear Hide protected operating system files. This lets File Explorer and dir /a /s include more content in totals for items that the current account can access.
    2. Compare File Explorer with dir /a /s output. From Command Prompt, create a full listing such as: dir d: /a /s > c:\d-dir.txt This helps identify whether the discrepancy is caused by items that are hidden or inaccessible to the current account.
    3. Investigate permission-related gaps. File Explorer and dir /a /s only report files and folders that the current account can access. If backup tools report more data than File Explorer, that usually means some folders are excluded by NTFS permissions. After locating inaccessible items, permissions can be reviewed or changed from the folder or file Properties > Security tab.
    4. Be careful when using File Explorer to open protected folders. If Continue is selected on a folder that requires administrative access, Windows Explorer can add the user account to the folder ACL. That can change permissions unexpectedly and affect security audits or application behavior. To avoid altering permissions, use an elevated tool instead of File Explorer, such as Command Prompt, PowerShell, or Computer Management.
    5. Check whether the issue is really hidden or system-protected storage. Low-space or incorrect size reporting can occur when applications create large temporary files in hidden or system-protected folders. These files may not be reported accurately by standard File Explorer folder-size views.
    6. Use backup reporting to find inaccessible content. A documented method is to generate dir /a /s output, then run ntbackup in Advanced Mode with a Detailed backup log for the whole volume, and compare the backup report with the dir output. Because backup can access all files, this comparison can reveal folders that File Explorer does not count.
    7. For effective access checks on file shares, avoid UNC paths in the affected scenario. On Windows 8.1 and Windows Server 2012 R2, viewing effective access for a file or folder on a non-Microsoft SMB 3.0 server can fail with 0x80070057 when using a UNC path. Mapping the share to a drive letter works around the issue and allows effective permissions to display.
    8. Escalate when permissions or names are abnormal. If a folder has no Security tab, permissions cannot be reassigned, access returns Access is denied, or files have invalid or reserved names that cannot be renamed or deleted, the documented guidance is to contact Microsoft Support.

    The supported causes in the documentation cover:

    • hidden and protected operating system files not included in normal views
    • NTFS permission restrictions
    • File Explorer changing ACLs when Continue is used
    • hidden temporary files consuming space
    • effective access failures on certain UNC share scenarios

    The context does not provide documented guidance for symbolic link analysis or NTFS metadata inspection beyond permissions and visibility behavior.

    References:

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  2. Hoang Le Huy 1,600 Reputation points Independent Advisor
    2026-11-05T10:08:47.9733333+00:00

    Hello Chang Min,

    When File Explorer reports folder sizes that do not match expectations, the discrepancy is often caused by one of four factors: permissions filtering, symbolic links/junctions, filesystem metadata behavior, or the way Explorer calculates folder sizes. Explorer only counts files the current user can access, so two users can see different folder sizes for the same directory if NTFS permissions prevent one user from traversing or reading part of the folder tree.

    You should also determine whether the directory contains junction points, symbolic links, mount points, or reparse points. Depending on the tool being used, linked content may be counted once, multiple times, or excluded entirely. This is a common reason why Explorer, PowerShell, backup software, and third-party disk analysis tools report different totals for the same path.

    Another important consideration is NTFS metadata and storage allocation. The logical file size, allocated size on disk, deduplication status, compression, sparse files, and Volume Shadow Copy data can all affect reported usage. In environments with large numbers of files, Explorer's folder size calculation may also be incomplete or delayed because it performs a recursive scan and is not designed as a disk-usage analysis tool.

    To identify the root cause, compare the reported size using multiple methods and verify whether inaccessible files, linked directories, or special filesystem attributes are present. If the discrepancy appeared recently, also review storage-related events in Event Viewer, run filesystem integrity checks, and confirm there is no corruption affecting directory metadata. In most cases, the issue is caused by permissions, reparse points, or differences in how tools interpret NTFS structures rather than actual data loss.

    If my answer is useful for you, please hit Accept the answer for me please.

    HL.

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