Citrix's Desktop as a Service (DaaS) product includes a lightweight, hardened second operating system called UniconOS (once called "eLux") to offer Windows customers a write-protected file system Citrix says is secure against computer viruses and other malware. Nerds.xyz reports:

According to the company, the environment remains isolated from the Windows filesystem and uses Secure Boot protections covering the shim, bootloader, kernel, and initial RAM filesystem. That separation matters when ransomware encrypts Windows or a faulty update leaves the operating system trapped in a boot loop. Instead of repairing Windows immediately, an employee can boot into UniconOS and use Citrix DaaS to acc...