compress drive to save disk space

[malagash]

I have a user that checked the box "compress drive to save disk space" of her C drive. Even with all startup items disabled the unit is painfully slow to boot. I suspect that the compression option is the culpret and I want to uncheck it to see if this is the case.
Question is, if I uncheck the option do I risk losing any data?
Is there a safe way to uncheck the option?

Thanks in advance

 

[kmcferrin]

As long as you have enough free disk space to store all of the uncompressed data, you should be fine. Otherwise you will get an error.

And yes, that's probably what is slowing down the PC.

 

[malagash]

thanks KM