Microsoft Fixes Windows 11 Bug That Could Waste Up to 500GB of Storage

Microsoft has addressed a Windows 11 bug that could consume hundreds of gigabytes of disk space, as part of the July 2026 Patch Tuesday update. Included in KB5101650 for Windows 11 versions 24H2 and 25H2, the fix targets an issue affecting the Capability Access Manager service that caused a system log file to grow abnormally large.

Unlike many of the new features introduced in the update, this storage fix is applied immediately after installation.

What Caused the Storage Problem?

The issue was linked to the CapabilityAccessManager.db-wal file, a write-ahead log (WAL) used by the Windows Capability Access Manager service, which handles application permissions.

Under normal conditions, this file occupies only a few megabytes of storage. However, a bug caused it to grow uncontrollably on some systems, reaching hundreds of gigabytes—in extreme cases, up to 500GB.

As the file expanded, users could see their available storage rapidly disappear despite having plenty of free disk space.

KB5101650 Delivers the Fix

Microsoft resolved the issue with Windows 11 update KB5101650.

Unlike the update’s new features, which are being rolled out gradually, the storage fix takes effect immediately after the update is installed.

Microsoft’s official release notes simply state:

“[Storage] This update improves disk space usage for the CapabilityAccessManager.db-wal file.”

Existing Large Files May Require Manual Cleanup

While the update prevents the log file from continuing to grow, Microsoft has not confirmed whether oversized CapabilityAccessManager.db-wal files are automatically reduced after installing the patch.

Reports from users who tested earlier preview builds suggest that existing files may remain unusually large until they are manually removed using Microsoft’s recommended procedure.

How to Check the File Size

After installing KB5101650, users can verify whether the log file is still consuming excessive storage.

One method is to run the following command in an elevated Command Prompt:

robocopy "C:\ProgramData\Microsoft\Windows\CapabilityAccessManager" "%TEMP%\CAMCheck" /L /B /R:0 /W:0 /BYTES /NP

Alternatively, users can inspect the file using disk analysis tools such as:

• WizTree
• TreeSize
• WinDirStat

Search for CapabilityAccessManager.db-wal and check its size.

• If the file is only a few hundred kilobytes or several megabytes, everything is functioning normally.
• If it is several gigabytes or larger, Microsoft recommends following its official cleanup procedure before deleting the file, as removing it incorrectly could cause system issues.

A Small Fix with a Big Impact

Although the bug affected only a subset of Windows 11 systems, it had the potential to waste enormous amounts of storage space. By including the fix in KB5101650, Microsoft has stopped the abnormal growth of the CapabilityAccessManager.db-wal file, helping prevent future storage issues while allowing affected users to reclaim valuable disk space after performing any necessary cleanup.