After months of user reports and a baffling wave of disappearing disk space, Microsoft has shipped a fix for a Windows 11 bug that can secretly swallow up to half a terabyte of storage. The patch, delivered in optional update KB5095093, stops a hidden system file from bloating out of control on PCs running Windows 11 versions 24H2 and 25H2. For anyone who has watched their drive fill up with no clear cause, this update may finally bring relief.

A Privacy Log That Became a Storage Monster

The troublesome file is CapabilityAccessManager.db-wal, a write-ahead log associated with the Windows component that tracks application access to privacy-sensitive resources such as the camera, microphone, and location. Normally, the entire Capability Access Manager folder takes up less than 4MB, with the WAL file itself hovering around 1.6MB. On affected machines, however, repeated permission-related events cause writes to pile up faster than Windows can consolidate them. The result: a log file that grows without bound.

Reports from users and investigations by Windows Latest and CyberShack put the file size between 70GB and just over 200GB in many cases, with one extreme instance reaching approximately 513GB. Because the file hides in C:\ProgramData, a directory that is both hidden and protected, it easily escapes notice. Windows may attribute the lost capacity to generic "system storage," leaving users clueless about where their free space has gone.

The real-world impact is immediate. A nearly full system drive can prevent Windows Update from staging packages, cause applications to fail, and leave little room for documents or media. Small SSDs are especially vulnerable—even a 50GB runaway file can consume most of their remaining headroom.

Microsoft Acknowledges the Issue—Quietly

KB5095093, released on June 23, 2026, advances Windows 11 24H2 and 25H2 to builds 26100.8737 and 26200.8737 respectively. On June 29, Microsoft amended the update’s change log with a terse note: it “improves disk-space usage for the CapabilityAccessManager.db-wal file.” That is the closest thing to an official advisory, but it falls well short of a full root-cause analysis.

The company has not disclosed which specific applications or events trigger the runaway logging, how many devices are affected, or whether the problem was introduced by a particular cumulative update. Community investigations point tentatively to location access as one possible culprit—a Tech Community post described continuous writes from the camsvc service when software repeatedly requested location. Turning off location services reportedly stopped the growth on that machine, but that workaround is case-specific and should not be treated as a universal fix.

Microsoft’s deliberately sparse wording also leaves one practical question unanswered: does installing the fix automatically shrink an already bloated WAL file, or merely prevent further expansion? Until more post-update reports surface, users should not expect hundreds of gigabytes to reappear instantly after a reboot.

Is Your PC Affected? Here’s How to Check

The safest method doesn’t require hacking protected folders. Open Settings, go to System > Storage, click “Show more categories,” then open “System & reserved.” A normal reading for system files generally sits below 40GB, though factors like hibernation, virtual memory, and restore points can push it higher. A figure in the hundreds of gigabytes, however, is a red flag that warrants immediate investigation.

For a precise check, storage-analysis tools like TreeSize, WizTree, or WinDirStat can peer into protected directories when run as administrator. A built-in alternative uses Robocopy in backup mode, which lists files without altering permissions:

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

Look for CapabilityAccessManager.db-wal in the output. A few megabytes is normal; a size measured in gigabytes that continues to climb signals that the PC is affected.

Network administrators should not rely on the overall “System & reserved” number as a fleet-wide detection rule. Hardware, page-file policies, and hibernation settings vary too much. Checking the actual WAL file size gives a far cleaner signal.

What the Patch Does—and Doesn’t Do

KB5095093 modifies the component’s behavior to stop the uncontrolled bloat. Users who need the fix immediately can install it through Windows Update under Advanced options > Optional updates, or grab it manually from the Microsoft Update Catalog for x64 and Arm64 devices. Because this is a non-security preview release, it may not be approved under policies that deploy only mandatory security updates.

For most people, waiting for the July 2026 Patch Tuesday release—expected on July 14—is the lower-risk route. At that point, the correction should roll into the regular cumulative update and reach normally managed PCs without extra steps. If the file is already expanding rapidly or has left too little room for Windows Update to function, installing KB5095093 sooner becomes more urgent.

The Danger: Why You Shouldn’t DIY

Well-intentioned forum advice sometimes suggests deleting or renaming the oversized WAL file from Safe Mode or the Windows Recovery Environment. While Windows can regenerate the file, this is not Microsoft’s documented remedy. Taking ownership of the protected directory, modifying permissions, or deleting a live system file while Windows is running creates avoidable risk and may obscure whether the update itself repairs the existing data.

Disabling the Capability Access Manager service is even more hazardous. The service underpins Windows’ permission handling, and community testing has linked disabling it to additional application and network problems. Turning off privacy features like location might slow growth on some systems, but it changes expected functionality and does not replace the servicing fix.

Next Steps: Install and Monitor

The recommended sequence is straightforward:
1. Confirm the file size using a read-only method.
2. Install the corrected Windows build—either KB5095093 now or the July cumulative update when available.
3. Reboot.
4. Monitor the file to see if it stabilizes and whether previously occupied capacity is reclaimed.

Administrators can deploy the patch through standard channels, but they should verify the July cumulative update’s contents before treating deployment as confirmation that the mitigation is present. The immediate aftermath of broad deployment will reveal whether Microsoft’s fix not only stops new growth but also cleans up the enormous files already stranded on affected PCs.

What Comes Next

This bug has been a quiet but painful annoyance for months, partly because Microsoft never listed it prominently on the Windows release health dashboard. The patch itself is welcome, but the company’s reluctance to share a full root-cause analysis or acknowledge how many devices are affected leaves a lingering transparency gap.

Windows 11’s storage management has improved over time, but incidents like this remind users that hidden system files can still run amok. The coming weeks will show whether the July update provides a complete cleanup and whether other, similar logging components might be prone to the same kind of runaway growth. For now, checking that one stubborn WAL file and applying the fix is the fastest way to reclaim lost gigabytes.