"Compress your OS drive" under Disk Cleanup

Sorry for a long reply but I encountered this myself and have carefully checked what I have posted by comparing my 3 PC's one of which has not been updated as its not been connected to the internet in recent weeks

This has only just started to appear as it does after applying the  LATEST FEBRUARY 2019 Windows Updates.

To explain further this option didn't present on previous versions. It may have been there but it didn't present itself as it does now on the disc clean up. 

What it does if YOU DO NOT untick it is it then compresses your OS drive and gives you back whatever space it saves you - in the OP's case it would give them 10.4GB extra space if they DIDNT UNTICK IT

The issue is that if you take the option you will then find that every single folder or even video every word document will now have two blue arrows against it. You will also find to some extent that your PC runs slower dependant on its capabilities

You will also find that if you then right click on your OS drive then click properties that the box marked " compress this drive to save disk space " will be ticked.

So once again to recap

1. it has only presented as standard under disc clean up with the latest updates
2. if you do a disc clean up with it ticked you will indeed save some space
3. If you do a disc clean up with it ticked your PC may seem slower
4. If you do a disc clean up with it ticked you will then find blue arrows against every folder you have

This has happened with the latest February 2019 updates

If you do not run a disc clean up with it ticked then pretty much nothing will happen as you will only gain the space if you allow it to compress your OS files and folders untick it and it wont

If you do run a disc clean up with it ticked then the things in 3 and 4 above will happen 

If you do run disc clean up with it ticked and then want things back as they were then the only way I have found to return to its previous state is to right click on my OS drive (C Drive) then click properties 

And then untick hat the box marked compress this drive to save disk space 

This then instigates a process that takes around 10 or more minutes to complete obviously the more files and folders you have the longer it takes my pc is quite light in whats on it

This new feature literally eats around 80 GB of my hard drive space, after trying to clean it some of the files started to appear with the compression sign even though I didn't check the compress drive option.

Can anyone from Microsoft please shed some light on this creation and how to get rid of it???

Or how can we roll back the windows update that introduced this failure??

My post on page 1 explains how to revert back 

Namely:

The only way I have found to return to its previous state is to right click on my OS drive (C Drive) then click properties 

And then untick  the box marked compress this drive to save disk space

This then instigates a process that takes around 10 or more minutes to complete obviously the more files and folders you have the longer it takes my pc is quite light in whats on it

ok... how bout this: I did nothing... my "compress to save disk space" box has never been checked...but all of moment... the blue arrows showed up on all folders after the update.  The "save disk space " box is still unchecked , and i hve about 50 gb now in the disk cleanup.

Hello,

My name is Patricia and I am an Independent Advisor. I am here to help you today.

That-s quite normal as you probably didn't check Compress this drive on C: drive and you are right not to do it.

It results in loss of power and speed.