If you specifically need the legacy OS Selector for an older system, you would have to find a licensed copy of Acronis Disk Director 11 Home , though it is no longer officially supported. 1569:Acronis OS Selector
To use the modern equivalent, you must download the latest version of Acronis Disk Director . 1. Prerequisites & Preparation
As modern PCs moved from BIOS to UEFI, the traditional way OS Selector hooked into the boot process became technically difficult and eventually unsupported in newer Disk Director versions. The 2021 Reality: A Search for a Phantom