Windows 10 compressed files take up all the free space - strange behaviour



I tried to resolve the issue myself for some time with no results and I didn’t find any answers on it in the forum, so I decided to post a question here.


I have a great problem with my wife’s laptop – I am facing the dreaded “Windows 10 Auto compression of files to save space” issue.



My wife once a month backs up photos and videos from her phone to the laptop where she processes them and then backs them up to Synology Disc Station. Unfortunately, she uses a folder created on her Desktop, so it resides on C drive (C:\Users\User_name\Desktop\ProblemFolderWithVideos). Last time she copied the videos from her phone to her laptop the auto compression obviously kicked in due to an insufficient space on C drive. I will refrain from commenting the “usefulness” of this feature in these scenarios while copying files somewhere where there is no space for it and I will try to get to the point.

After the successful copy process all the mp4 videos in the folder which are now marked with those two blue arrows (Image 01) and have the “Compress contents to save disk space” (Image 02) have enormous size about 52 GB and 38 GB on disk (Image 03). This information is ridiculous since the C drive itself is 68 GB in size. (Image 04).

Image 01.jpg


Image 02.jpg


Image 03.jpg


Image 04.jpg


So, the number of the mp4 files times their size indicated in file properties is much higher than the drive capacity. Also the original size of the mp4 files was of course significantly smaller (about 500MG – 1.5GB per video). The C drive seems to be full all the time and the compressed mp4 files always take up all the free space in this drive if you create the free space. I cannot switch off the compression on the files itself or the folder which contains these files because the system always tells me there is insufficient space to perform decompression. When I try to move these files to any other disc USB external HDD, Synology the scenario is always the same. There is not enough space to move even a single mp4 file. It looks like every single file makes itself to appear as large as the space which is available on any disc which you try to copy it to. Ridiculous I know, but that is how it looks like.


My wife doesn’t have the original files on phone, so I need to somehow decompress these files if it is possible and then switch off the NTFS auto compression itself for good.

System information:

Windows 10 Enterprise

10.0.19042 Build 19042

x64 based


Can anyone please help me to resolve this issue? Did anyone encounter something like this?

Thank you very much for any response or hit how to resolve this.

Kind regards,


Zdeněk Neustupa

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