How to Install Windows 10 in Compact Mode to Save Space

Ultracompact laptops, often called cloudbooks, flood the market with just enough hardware to run Windows 10 while relying on a solid-state drive (SSD) to make up for any lack of speed. The catch is that the SSD is usually small, often around 32 GB. While you can expand storage technically using memory cards, USB drives, or external drives, if you're planning to reinstall Windows 10, you might prefer to enable compact mode and apply a few extra tweaks to gain several gigabytes without an extreme drop in performance.

I admit this issue isn't very common on desktop computers. The flexibility of SATA ports and the progress of new interfaces let us add storage easily and at increasingly reasonable prices. You might remember our article on the Western Digital Blue, a 1TB SSD for under 200 euros. Today we can get that drive for less than 135 euros, and it seems like prices will keep falling. However, many ultraportable computers can't accept expansions unless you go 'outside' with external hard drives and memory cards. At the same time, these machines only support Windows 10, and depending on usage, their 32 or 64 GB drives fill up quickly. So what can we do? A partial solution is to install Windows 10 in compact mode.

How to Install Windows 10 in Compact Mode

The /CompactOS feature in Windows 10 is very useful for gaining space when the system is already installed, but if you're starting from scratch, there's another route. The first step is to proceed with the standard Windows 10 installation until you reach the partition size section. There, delete all partitions (or the one containing Windows), create a new one, and press Shift+F10. This will open a system console with the prompt inside the Sources folder. Then run diskpart, ask for a list of available volumes with list volume, return to the partition menu, format the new partition, go back to the console, and repeat the list volume command. One of the volumes that showed RAW will now have a drive letter assigned. You can exit diskpart then, but don't forget the letters of the partition and the drive with installation files (in our example, F and D respectively).

The next phase is to deploy the Windows 10 image using the DISM tool with this command:

DISM /Apply-Image /ImageFile:(letradeunidad1):\sources\install.wim /Index:1 /ApplyDir:(letradeunidad2):\ /Compact

«letradeunidad1» is the drive letter containing the Windows 10 installation files (D in our example), and «letradeunidad2» is the letter assigned to the new partition (F). Don't forget the /Compact modifier at the end—that's the key. Press Enter and wait. Windows 10 will install with /Compact applied to the entire partition. Once the process finishes, run one more command to create boot files: bcdboot (letradeunidad2):\Windows. Type exit to leave the console, close the installer, and let the computer reboot.

That's it! The rest proceeds just like a traditional Windows 10 installation (Cortana greeting, region, privacy, etc.). In our test, we used a 32-bit image, and the Windows folder takes up 4.25 GB out of a compressed (and unoptimized) total of 7.24 GB, a reduction of 41 percent.

Is there anything else to do? Yes: you can adjust the virtual memory size (Windows manages it automatically by default), enable reduced hibernation mode (powercfg /h /type reduced), or disable it completely and recover more space (powercfg /h off). Don't stop trying!