A strange bug in Windows 11 is quietly draining storage space: a single system file can grow out of control and consume up to 500 GB on your system drive. If your disk suddenly seems much fuller than it should be, this might be why.
What is causing the problem?
The culprit is a file called CapabilityAccessManager.dbwal, which normally logs system access events for things like microphone, camera, and location permissions. Under normal circumstances it stays in the megabyte range. Due to a bug, the related service loses control and writes data continuously until hundreds of gigabytes are used up.
How to check if you are affected
Open Settings and go to "System" > "Storage". Click "Show more categories" and inspect the "System & reserved" section. If you see far more storage consumed than the typical single-digit gigabyte value, you are likely affected. The consequences are noticeable: the system slows down, app installations fail, and downloads cannot complete.
When will the fix arrive?
Microsoft has acknowledged the issue and is providing a fix through update KB5095093. For home users, the easiest path is to wait until July 14, 2026, when the patch will be delivered automatically via Windows Update as part of the regular monthly rollup. If you prefer not to wait, the update is already available for manual download through the Microsoft Update Catalog.