If you do not have the specific 8.5.1 installer files and cannot find them on the NI portal:
To download the LabVIEW Runtime Engine 8.5.1 in 2021, follow these steps: labview runtime engine 85 1 download 2021
LabVIEW 8.5.1 was a specific point release released by National Instruments (now Emerson NI) around 2008. It introduced several stability improvements over the base 8.5 release. If an engineer deployed an executable built in LabVIEW 8.5.1 in 2008, that specific machine requires the exact 8.5.1 engine to run; version 8.5 or 8.6 will often fail to execute the code correctly. If you do not have the specific 8
Running 2008-era software on 2021 hardware requires awareness of operating system limitations: LabVIEW Run-Time Engine (RTE) - VA.gov and OS support.
While NI does not promote LabVIEW Runtime 8.5.1 as a “2021” release, it remains accessible to registered users through legacy channels. In 2021 and beyond, obtaining it requires patience and adherence to official sources to avoid security risks. For new deployments, migrating the application to a newer LabVIEW version is strongly recommended, as NI has since improved runtime deployment, security, and OS support.