[Windows 10 Bug] Windows Update Files Taking 3.99 TB Space in Disk Cleanup

Today while doing some regular maintenance tasks on my Windows 10 PC, I found a weird issue. I regularly run Disk Cleanup (Cleanmgr.exe) tool and use other methods to gain extra free space on my hard disk drive and today when I launched Disk Cleanup tool, I found that Windows Updates were taking 3.99 TB hard disk space according to Disk Cleanup program.


In Disk Cleanup tool, when I clicked on "Clean up system files" button, it showed that 3.99 TB space can be recovered by cleaning Windows Updates leftover/cache files which is actually impossible as the size of C:\ partition on my HDD is only 50 GB and the total size of the hard disk is 1 TB, so how can Windows store 3.99 TB updates files on the hard disk?

After some research I found that its a known bug/issue which starts happening after installing KB3194798 update in Windows 10.

Actually there is a system folder "C:\Windows\WinSxS" which is known as "Windows Side by Side" and "Windows Component Store". This folder contains many hard links to system files and Windows updates for compatibility issues. Using hard link concept, Windows can keep multiple instances of same system file in different places virtually. So a system file can reside in more than one folder but there will be actually a single real file and other instances are just copies or hard links of that file.

Now it seems that KB3194798 update also stores multiple hard links of its system files in various folders such as "C:\Windows\SoftwareDistribution", WinSxS, etc, which confuses Disk Cleanup tool and it miscalculates the size of Windows Update cleanup. It seems Disk Cleanup tool doesn't check for hard links while calculating the size of the folders, hence it also counts the size of hard links and performs inaccurate calculation.

So Windows Update is actually not consuming the mentioned 3.99 TB space on your hard disk, its Disk Cleanup program which is wrongly calculating and showing the size.

To fix this bug/glitch, you can just select "Windows Update Cleanup" option in Disk Cleanup and click on OK button. It'll take around 20-30 minutes in completing the task and after completion, if you check Disk Cleanup tool again, it'll no longer show Windows Update Cleanup option in the list. It'll be automatically fixed.

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Posted in: Windows 10

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  • It's only a cosmetic bug and will be fixed soon.

  • nice one! been suffering with this bug for merely a month. Good thing you shed some light about this bug in this post. Very informative. Keep it up Mr. VG. --Your big fan from Philippines.

  • another bug that I encountered recently in LTSB is when you right click in empty area of start menu tiles or its side bar and after that right click in desktop area then context menu goes blank or sometime like this :


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