If your Windows 11 machine has been mysteriously running out of drive space and you haven’t been able to figure out why, you may not be imagining things, and it may not be your fault.
Microsoft has confirmed a storage bug tied to Windows 11’s Capability Access Manager, the system service that tracks and manages app permissions for things like your camera, microphone, and location. The culprit is a file called CapabilityAccessManager.db-wal, a write-ahead log that’s supposed to stay a few megabytes but can, under this bug, balloon into the hundreds of gigabytes. Some affected users have reported the file consuming over 500GB on its own.
Microsoft’s official fix arrives via KB5095093, which shipped as an optional preview update on June 23 and is set for full automatic rollout through July’s Patch Tuesday. The acknowledgment itself is almost comically understated: the release notes simply read, “This update improves disk space usage for the CapabilityAccessManager.db-wal file,” with no mention of the scale of the problem or a public explanation of the root cause. The bug was first surfaced by Windows Latest and community reports on Reddit and Microsoft’s own support forums, not by Microsoft proactively flagging it.
If you want to check whether you’re affected before the patch lands: run robocopy "C:\ProgramData\Microsoft\Windows\CapabilityAccessManager" "%TEMP%\CAMCheck" /L /B /R:0 /W:0 /BYTES /NP from an elevated prompt and look at the size reported for CapabilityAccessManager.db-wal. A few megabytes is normal. Multiple gigabytes, and climbing, means you’ve likely been hit. The folder itself is protected, so don’t try to poke around it directly in File Explorer, and resist the urge to just delete the file manually. Install KB5095093 through Windows Update’s optional updates section instead, or wait for it to arrive automatically next week.
One open question nobody, including Microsoft, has fully answered yet: does the update actually reclaim space an already-bloated file has consumed, or does it just stop the file from growing further going forward? Based on the available reporting, that’s unclear, and Microsoft’s terse release note doesn’t clarify it either way. If your drive is already full because of this, install the update, then re-check the file size afterward rather than assuming your storage is automatically restored.
This isn’t a headline-grabbing exploit or a security hole. It’s the more mundane, more common kind of Windows bug: a background service quietly misbehaving for what reporting suggests has been the better part of a year before anyone at Microsoft owned up to it publicly. If your SSD has felt suspiciously tight lately for no obvious reason, this is worth ten minutes of your evening to check.