Microsoft Fixes Major Storage Consumption Issue with July 2026 Security Update

The July 2026 Patch Tuesday update has arrived, resolving a critical storage bug affecting some users since March. The Windows 11 KB5101650 update addresses the Capability Access Manager issue, which had been silently occupying substantial storage space on system drives. As part of the standard rollout phase, this update is automatically installed on all eligible PCs without requiring a phased deployment.

Details About the Storage Fix

Earlier this month, Windows Latest reported that the bug could consume up to 500GB of storage. The issue was linked to a file called CapabilityAccessManager.db-wal, which expanded uncontrollably until the C: drive was full. Notably, Windows did not display any information in the Settings app regarding the file's existence or size.

Despite the severity of the bug, Microsoft described the fix in understated terms: “[Storage] This update improves disk space usage for the CapabilityAccessManager.db-wal file.”

What Changed for CapabilityAccessManager.db-wal in the July Update

The storage fix was initially introduced in the June optional update (KB5095093), although it wasn't documented right away. Microsoft added a note about the storage improvement on June 29, six days after the update's release. The July KB5101650 update includes all non-security changes from the June preview update and applies the fix to the following builds:

• Build 26200.8875 for Windows 11 25H2
• Build 26100.8875 for Windows 11 24H2

This update is part of the standard rollout process, ensuring all eligible devices receive it simultaneously, unlike Microsoft's staggered deployment for certain new features. Once installed, the storage fix becomes effective.

However, Microsoft's use of the phrase—“improves disk space usage”—indicates that the update prevents further growth of the WAL file but does not guarantee automatic reduction of files that have already grown significantly. Users who installed the June preview update noted that their oversized files remained unchanged until they manually intervened.

As such, the July update should be viewed as a preventative measure against further growth, though users may still need to manually address existing storage issues.

Understanding the CapabilityAccessManager.db-wal Growth

The Capability Access Manager service (camsvc) logs app requests for camera, microphone, location, and screen capture access. These events are stored in a SQLite database located at:

C:\ProgramData\Microsoft\Windows\CapabilityAccessManager\

The database consists of two files:

• CapabilityAccessManager.db – The main database file.
• CapabilityAccessManager.db-wal – A write-ahead log (WAL) that temporarily holds database changes.

On affected PCs, the checkpoint process that merges the WAL into the main database failed to execute, leading to unchecked growth of the WAL file. IT admin Max Allen documented the issue across approximately 10,000 endpoints on his blog, noting that apps with frequent write operations exacerbated the problem. Examples include:

1. Rainmeter’s WiFiStatus Plugin: This plugin queried the database about 10 times per second, causing a WAL file to grow to 30GB within 10 hours.
2. Dell’s SmartByte: A network utility that logged over 9,000 writes in just 30 minutes, contributing to significant file growth.
3. GeoComply: A location-verification app used by online sports betting platforms, which caused similar issues.

While these applications accelerated the problem, they were not the root cause. The checkpoint logic within camsvc was broken, though the database itself remained functional when manually managed using third-party tools like DB Browser for SQLite.

Microsoft’s Internal Response and Public Acknowledgment of the Bug

Microsoft privately acknowledged the bug on May 13, 2026, following a support case filed by Max Allen. The company provided a manual workaround at the time, which involved booting into Safe Mode, stopping camsvc, and manually deleting the WAL file. Public acknowledgment of the issue came later, on June 29, when it was included in the changelog for the June preview update.

Interestingly, the Windows Release Health Dashboard did not list the bug among known issues, despite its widespread impact. Data from Allen’s fleet of managed devices revealed the following:

• 59% of devices: WAL files exceeded 1GB.
• Several hundred devices: WAL files grew by more than 10GB in a single week.
• One device: Reached a WAL file size of 332GB.

In contrast, another scan of 8,000 devices by different IT admins found only one WAL file exceeding 500MB, highlighting the bug's uneven distribution across different setups.

How to Check If Your PC Is Affected

To check if your PC is impacted, follow these steps:

1. Go to Settings > Storage > Show more categories > System & Reserved.
2. Check the size of System files. If it is in the hundreds of gigabytes and cannot be explained by a hibernation or page file, the issue might be present.

To confirm, 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

If the CapabilityAccessManager.db-wal file size is several gigabytes or continues to grow, your system is affected.

How to Reclaim Storage After Installing KB5101650

After installing the July update, restart your PC and check the WAL file size. If the file has been reduced to a few hundred kilobytes, no further action is necessary. If it remains large, follow these steps:

1. Boot into Safe Mode.
2. Stop the camsvc service by typing net stop camsvc in Command Prompt.
3. Manually delete the WAL file, leaving other files in the folder untouched.

If you encounter access issues, resetting permissions with this command may help:

icacls “C:\ProgramData\Microsoft\Windows\CapabilityAccessManager” /reset /T /C

If your drive is completely full and Windows Update cannot proceed, manually clearing the WAL file is the only immediate remedy. However, this should be done as a last resort.

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