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💾 C Drive Full Fix

C Drive Suddenly Full After Windows Update Causes and Safe Cleanup Order

Yesterday the C drive had space. Today it is red and full — and nothing new was installed. After a Windows update this has two very different causes: a known bug file that can grow to hundreds of GB, and normal update leftovers. This guide separates them and cleans both, in the safe order.

✍️ Technical Anshu🪟 Windows 11⏱️ 10 minute fix
🎥 Watch the full process in the video — the KB5095093 storage bug and the cleanup, shown on a real PC

This is the call every IT engineer knows: "My C drive was fine yesterday, the update happened, and now it is 100 percent full." Do not start deleting folders at random. There are two stories here. Story one is a real Microsoft bug fixed by update KB5095093, where one permission-log file grows without stopping. Story two is the normal weight every big update leaves behind — the old Windows copy, download caches and setup files. Measure first, identify which story is yours, then clean in this order.

Settings > System > Storage > Local Disk (C:) — example PC
System files212 GB
Apps31 GB
Temporary files17 GB
Free space0.4 GB
A normal Windows system takes roughly 25 to 40 GB under System files. When that one line alone shows 100 GB or more, a single runaway file is hiding inside it — check the bug first, not the dustbin.
Example Storage screen of an affected PC. Your numbers will differ — the pattern is what matters.
1

Measure First — How Much Space Actually Vanished

Cleanup without measuring is guessing. Two minutes of checking tells you exactly which fix you need.

  1. Open Settings → System → Storage and note the free space on C:
  2. Open System & reserved → System files. If this line alone is in the hundreds of GB, skip to Fix 2 — that is the bug signature
  3. If the weight sits in Temporary files and a Windows.old folder instead, your case is normal leftovers — Fixes 3 and 4 are yours
  4. For a full picture, run a free scanner like WizTree as administrator and sort by size — one giant file is a bug, many medium folders are normal weight
2

Check the Bug File — CapabilityAccessManager and KB5095093

This is the cause shown in the video, and it is now confirmed by Microsoft. The Capability Access Manager — the Windows component that logs app permission requests for camera, microphone and location — keeps a log file named CapabilityAccessManager.db-wal. It should stay around 2 to 4 MB. On Windows 11 24H2 and 25H2 builds below 26100.8737 / 26200.8737, it can grow past 200 GB and fill the drive.

  1. Check your build in Settings → System → About. Below those numbers means the fix is not installed yet
  2. To measure the file safely, open Command Prompt as administrator and run this read-only check — it only lists, it copies nothing: robocopy "C:\ProgramData\Microsoft\Windows\CapabilityAccessManager" "%TEMP%\CAMCheck" /L /B /R:0 /W:0 /BYTES /NP
  3. The folder itself is protected, so an "Access denied" in File Explorer is normal — do not change its ownership or permissions
  4. The fix is an update, not a deletion: install KB5095093 or any later cumulative update from Windows Update and restart. The log is then folded back to normal size and the space returns
  5. If the drive is too full for the update to install, do Fixes 3 and 4 first to make room, then update immediately

Do not delete the file by hand and do not disable the Capability Access Manager service — that breaks app permissions and has caused network trouble on real machines. The update is the supported repair.

3

Remove Windows.old — the Previous Windows Copy

After a feature update, Windows keeps your entire previous installation in C:\Windows.old so you can roll back. It is commonly 15 to 30 GB. Monthly security updates do not create it — feature updates do.

  1. First copy out anything personal still sitting inside Windows.old\Users — after cleanup it is gone for good
  2. Open Settings → System → Storage → Temporary files
  3. Tick Previous version of Windows and choose Remove files
  4. Understand the trade before you click: deleting it ends your option to roll back to the previous version. The standard rollback window is about 10 days, and Windows removes the folder by itself after that window anyway

Never delete Windows.old by dragging it to the Recycle Bin — its permissions fight back and leave a half-deleted mess. The Settings and Disk Cleanup routes are the supported ones.

4

Clear Temporary Files and the Delivery Optimization Cache

The same Temporary files page holds the rest of the everyday update weight.

  1. In Settings → System → Storage → Temporary files, tick Temporary Windows installation files — the setup working files an upgrade leaves behind
  2. Tick Delivery Optimization Files — cached pieces of updates and Store apps kept for sharing with other PCs. Clearing them is safe; Windows simply downloads again what it needs
  3. Tick Windows Update Cleanup if it is listed, plus ordinary Temporary files
  4. Leave Downloads unticked unless you personally know everything in that folder — that one is your data, not Windows weight
  5. Choose Remove files and let it finish
5

Shrink the Component Store with DISM

What is left is the component store — the pile of superseded update copies Windows keeps so updates can be serviced. Clean it only with the supported command, never by opening the WinSxS folder.

  1. Open Command Prompt or Terminal as administrator
  2. Run DISM /Online /Cleanup-Image /StartComponentCleanup
  3. Let it complete — on a heavily updated PC this can take a while and is not stuck
  4. Honest trade: after this cleanup, the superseded updates it removed can no longer be uninstalled individually. That is the normal, intended cost of the space
6

Restart, Verify, and Keep Headroom

Finish like a technician, not like a gambler.

  1. Restart the PC once — several cleanups complete their work across a restart
  2. Re-open Settings → System → Storage and compare with the number you noted in Fix 1. The recovery should be visible, not hoped for
  3. If the bug file was your cause, re-run the Fix 2 robocopy check after the update and confirm the log is back to a few MB
  4. Keep roughly 10 to 15 percent of the C drive free as working room. Updates need space to install; a drive kept at 99 percent full will keep producing this same emergency
🔴 Three things never to delete by hand: the Windows.old folder, anything inside WinSxS, and the CapabilityAccessManager folder. Every one of them has a supported route in this guide — Settings, Disk Cleanup, DISM, or the KB5095093 update itself.

🎥 Watch the Complete Video Guide

C drive full after the update — the bug check and the complete cleanup, shown live step-by-step.

▶️ Watch Full Video
❓ Common Questions (FAQ)

Is it safe to delete the Windows.old folder?

Yes, through Settings → Storage → Temporary files → Previous version of Windows, or through Disk Cleanup system files. It only removes your rollback copy of the previous Windows version. Copy any personal files out of Windows.old\Users first, and remember that once it is gone, rolling back to the previous version is no longer possible.

My System files show more than 200 GB. Is that normal?

No. A normal Windows 11 system uses roughly 25 to 40 GB of system files. A figure in the hundreds of GB is the signature of the CapabilityAccessManager.db-wal bug, fixed by KB5095093 or any later cumulative update. Check your build number in Settings → System → About: below 26100.8737 on 24H2 or 26200.8737 on 25H2 means the fix is not installed.

Will the KB5095093 fix arrive on its own?

Yes. KB5095093 was released as an optional update on 23 June 2026, and the same fix is included in the July 2026 Patch Tuesday cumulative update and every cumulative update after it. If your PC is affected and nearly full, do not wait — free a little space with the Settings cleanup first, then run Windows Update and restart.

This guide is based on the Technical Anshu C drive full after update video • Stuck on any step? Ask in the video comments — you will get a reply there 🙏