Ntfs file compression - how to remove from folders

Hi. I just noticed on my small 32GB netbook that a folder on the desktop has the blue arrows on it signifying that Windows 10 has compressed the folder and its contents on its own I guess because I don't have a lot of space left on the netbook.

I found this tutorial and used a reg file to disable compression:

Enable or Disable NTFS File Compression in Windows | Tutorials

I also right clicked the compressed folder/properties/advanced/ deselected compress contents to save disk space/ ok and this uncompressed the folder. I've noticed now that a macrium folder not in that folder is compressed.

My question is how can i tell which folder files have been compressed by windows besides just searching around? Is there an easy way to uncompress whatever it compressed in one action? Thanks.

Added: when i check the c drive, i can see a few folders have been compressed like dell and drivers.. the macrium folder is in documents.. its the mybackup files... should i just decompress these folders via right click/ properties?

Added: so thats what i did.. i dont see anything else that's been compressed. I wonder if that is connected to storage sense... I see its off now as well.

To answer part of your question- compressed folders (via Properties) should be shown in a different colour:

(See Help Downloaded - selected in the background)

The tutorial you cite simply removes the ability to compress files and folders by NTFS compression, as it says.

These may be of interest:
Show Encrypted or Compressed NTFS files in Color in Windows 10 | Tutorials

while this is historical about blue arrows:
Show Encrypted or Compressed NTFS files in Color in Windows 10

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This probably applies in your case:
Compress or Uncompress Windows 10 with Compact OS | Tutorials

Bear in mind you have very limited disk space- it is common for such systems that problems occur when upgrading (Windows.old is created e.g.)

You can find an extensive thread about a couple of weeks old about compressing the OS and its merits/overheads/demerits.

You can also find a number of threads about systems such as yours with 32Gb eMMC storage.

Examples:
How to free up space on 32GB tablet C Drive - Microsoft Community
Unable to update Windows 10 on PC with 32GB hard drive - cant - Microsoft Community

https://www.tenforums.com/general-support/67580-not-enough-space-hard-drive-windows-update.html
post #10

OS compression has apparently been built in to Windows installs without a clear explanation- the thread I mentioned discusses this. Some found the OS compressed and had no awareness of it or loss of performance. Whether it happens or not was not clear from that account- it seemed erratic. In your case, it would seem enitrely appropriate.

Win10 keeps compressing C drive files (new and old). Cannot stop it. Solved - Windows 10 Forums

Thanks dalchina.. That's a good thread. My OS was in a compact state (in 1803). I uncompressed it and lost about 2GB of space and have 4.3GB left. Everything seems fine otherwise. File/folders new folders etc are not auto compressing. I'm going to see if i can free up more space with disk cleanup/ccleaner. Maybe I'll block the update suspected of triggering this in future. I don't plan on updating to 1809 for a while. Could be my imagination but system seems snappier in uncompressed state.. not sure. But all seems well in any case.

When I query my system I get this:

>compact /compactos:query
The system is not in the Compact state because Windows has determined that, it
is not beneficial for this system.

which is what I would expect since I have a 500GB SSD boot drive (C:), about 1/2 full and two 2TB drives for data.