A Hidden Windows 11 Bug Quietly Swells Your C Drive by 100GB+ — the Patch Only Arrives July 14

If your C drive keeps shrinking even when you haven't installed new games or downloaded big files, it may not be your imagination. Windows 11 24H2 and 25H2 contain a deeply hidden bug: a system log file called CapabilityAccessManager.db-wal grows out of control in the background, swallowing up to 500GB or more of disk space.

💡 What You Will Learn

If your C drive keeps shrinking even when you haven't installed new games or downloaded big files, it may not be your imagination. Windows 11 24H2 and 25H2 contain a deeply hidden bug: a system log fi

Microsoft has acknowledged the bug, but in a distinctly quiet way — it quietly added a line to the KB5095093 update log released on June 23, with no dedicated announcement and no press release. The fix won't be pushed to all users until July 14, Tuesday's Patch Tuesday.

How does one log file eat 500GB? The culprit is CapabilityAccessManager.db-wal, the log database of Windows' Capability Access Manager service, which records app calls to permissions like camera, microphone, location, and screen capture. Theoretically this file should only be a few MB. But a known bug in Windows 11 24H2 and 25H2 sends the capability access manager service (camsvc) into an infinite loop, repeatedly writing entries to the log and inflating the WAL file.

Reddit users have already posted a screenshot of 513GB, while pagefile.sys and hiberfil.sys together accounted for just 29GB on the same system. Other users report values from 70GB, 110GB to 200GB — this is not an isolated case or a rare event.

Why it's hard to find: Windows' built-in storage management doesn't tell you which file is at fault. Open Settings → System → Storage and you'll only see 'System & reserved' eating several hundred GB, but not which specific file. The Windows Latest editor only grew suspicious when he saw 'System & reserved' taking 89GB on a freshly installed machine, and had to dig to find CapabilityAccessManager. Not everyone is affected — if your C drive has no unusual shrinkage during normal use, you're probably fine. But if C drive space keeps mysteriously dropping, this bug is very likely the cause.