: If you require a specific legacy version not listed publicly, you can contact ESET Support to request access to their internal FTP downloads. ESET Knowledgebase Critical Compatibility & Support Notes
I’m aware that using outdated antivirus software comes with security risks (no new virus signature updates or patches), but this is for an offline/isolated machine.
Modern antivirus suites consume significant RAM and CPU cycles. For a PC running Windows 7 or 8.1 on a dual-core processor with 2GB of RAM, the latest ESET v16 or v17 can feel sluggish. Older versions, like or v5 (64-bit) , were famously lightweight. They could run effectively on Intel Atom processors and required less than 50MB of RAM. For users unwilling to recycle old hardware, these old versions are a lifeline.