Microsoft Windows 11 bug inflates system file, consuming up to 500 GB of storage

A bug in Windows 11 causes the system file CapabilityAccessManager.db‑wal to grow unchecked, reaching sizes of 70 GB, 200 GB or even more than 500 GB. The oversized file occupies the “System & reserved” space on the C: drive, leaving users with dramatically reduced free storage. The issue has been reported on forums such as Reddit and confirmed by Microsoft in the notes of optional updates KB5095093 (June 2026) and KB5095091, with a broader fix scheduled for the July 2026 Patch Tuesday rollout.

Affected users can verify the problem by opening Settings → System → Storage, selecting “Show more categories,” and checking the “System & reserved” allocation. Work‑arounds include renaming the offending file in C:\ProgramData\Microsoft\Windows\CapabilityAccessManager or manually cleaning temporary update folders, but the recommended solution is to install the Microsoft update that addresses the bug.

The bug appears on Windows 11 PCs worldwide, regardless of language or region, and primarily impacts devices with limited SSD capacity, where a loss of several hundred gigabytes can render the system unusable.