Because these are modified versions of copyrighted software, you won't find them on official Microsoft sites. They are typically hosted on:
It’s common for these builds to idle at under 1GB of RAM. Download Windows Ultralight (22621 590) FBConan zip
By removing telemetry, Windows Defender, and dozens of background services, the OS feels significantly snappier than the stock version. Because these are modified versions of copyrighted software,
The installed size is often a fraction of the standard 20GB+ Windows installation. The installed size is often a fraction of
Often, Windows Defender and Windows Update are stripped or disabled. You are responsible for your own security.
While the idea of a "Windows Ultralight" build by FBConan sounds like a dream for anyone running an older laptop or a resource-heavy gaming rig, you should approach these custom ISOs with a mix of excitement and caution. What is Windows Ultralight (Build 22621.590)?
Since this is a third-party modification, you are trusting the developer hasn't included anything malicious (or unintentionally broken a critical system component). Where to Find It