Compress system files doesn’t show up in Disk Cleanup

One of the new features of Windows 10 is better file compression, which was intended to help Windows fit better in low-resource devices like tablets. But it’s helpful on computers with SSDs too. But for whatever reason that option doesn’t show up on mine.

But you can still compress your system files even if the Disk Cleanup utility (which you can also launch from the Free up disk space by deleting unnecessary files control panel) doesn’t show the Compress system files option.

Open an elevated command prompt. To do this, click Start, then type cmd, then instead of hitting enter, right-click on the command prompt and select run as administrator.

Type compact /compactos:query

If you get one of these two messages, the OS is not compressed:

The system is not in the Compact state. It will remain in this state unless an administrator changes it.

The system is not in the Compact state because Windows has determined that, it is not beneficial for this system.

If you get the latter message, that’s probably why it doesn’t show up in the GUI. But you can override this decision.

To compress system files, type compact /compactos:always

Compression saved me about 2 gigs of space, which was less than I hoped but worth having on a 90 GB SSD.

To undo it, type compact /compactos:never