Windows 10 Update copies entire C: partition as an update???

Hi. I've reinstalled win 10 on a few computers this month and the first update that comes along (a very time consuming one) copies the ENTIRE c: drive system partition's worth of date again to do this update??? The old partition info is put in a folder called "windows.old". What do they do this for? It is a huge waste of space? Can I just delete it???


Windows Forum Team
Staff member
This is normally after the Windows AU (Anniversary Update). You can delete it with the "Disk Clean Up" utility. There should be an option to clean up "Previous Versions of Windows" this will remove the Windows.old folder

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Fantastic Member
Premium Supporter
I think neemo meant AU=Anniversary Update. This folder gives you the ability to "rollback" your computer to a point in time just prior to the udpate's installation. This is important as the AU update (there are now 7 different builds of version v1607) starting on Aug. 2nd has really only been pushed out the last 3 weeks to consumer's computers in any numbers. They are causing many many W10 systems to crash and burn. This "rollback" feature is reminiscent of the built-in windows System Restore utility available on windows systems since XP. It might be worth mentioning, that if you are installing it on multiple computers that are different brands such as Dell & HP, it might be best to wait a week or so and make sure all your loaded applications are working BEFORE deleting the windows.old directory as neemo suggests. This way if you have a computer or two that gives you headaches such as loss of wifi network connectivity or loss of audio and reinstalling drivers doesn't fix it, you have a way to get back to a previous working version of W10 that was working such as v1511.:)

Another thing you can do if you have external hard drives available would be to use a solid W10 Image Backup program such as the free Macrium, Acronis, or EASETodo software programs and image each of these computers once you've "'stabilized them" and make sure they are working properly. Once you have these backup images in place on external media (you could also use a network server or Cloud backup), you could then go around to each computer and delete the windows.old directories, one computer at a time. Should one of them misbehave, or decide to just stop booting, or crash, or freeze, or hang and it's not easily repairable, you can just re-image that computer to an earlier version you have stored via your Image Backup program on external media in a matter of a few hours!:up: We do this a lot here those of us who are W10 Insider Testers; we voluntarily help Microsoft test new versions of W10. This might be a method that could help you.

Best of luck,:encouragement:


Windows Forum Team
Staff member
Lol, must of been a short between the keyboard and chair when I wrote that.

Yes I remember something about that update... thank you! I will fix it with the suggestion from Neemobeer :)

Axel PC

Well-Known Member
Just my 2 cents. I would keep it for a bit longer till you're sure you don't want/need to roll back to the previous Windows that was on that machine. I mean if the size of the file isn't taking away needed space it's not hindering the machine.

I'm speaking from experience. I uodated my desktop and 2 laptops to Windows 10 and each one had some sort of BSOD issues, hardware drivers, software compatibility, had to wait for Lenovo, Asus, and Samsung to issue driver fixes. Then in the mean time I or my wife had to deal with BSODs.

If I didn't delete the window.old folder I could've roll back the OS on my wife's laptop and she would have been much happier.

Just my 2 cents, hope it works out for you.

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Essential Member
Microsoft Community Contributor

The other reason for keeping you Windows.old folder for a week or so is that everything is stored in there, if you find that after the update some things are missing i.e. address books etc. you can retrieve then from there.

I have had instances when I needed to retrieve data from my .old folder after an update.

An easy way to remove the Windows.old folder is to run CCleaner with the Windows.old folder checked.

Windows will not let you just delete it.


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