Getting a legitimate copy of LabVIEW Runtime Engine 8.6 today requires care. National Instruments no longer prominently features this version on their main downloads page, but it is still available via their and Archive repositories.
For the LabVIEW Real-Time (RT) module, version 8.6 is legendary for its stability but also marks the end of an era. labview runtime engine version 8.6
Obtain the installer from the official NI website (search for "LabVIEW Run-Time Engine 8.6"). The LabVIEW Runtime Engine Version 8
If you no longer require LabVIEW Runtime Engine 8.6, proper removal is important to avoid conflicts with other NI software. Evaluate effort to recompile VIs in a modern LabVIEW version
LabVIEW, developed by National Instruments (NI), is a graphical programming environment used for designing and implementing control, test, and measurement systems. The LabVIEW Runtime Engine is a separate software component that enables the execution of LabVIEW applications on a target machine, without requiring a full LabVIEW development environment. This allows users to deploy and run LabVIEW applications on a variety of platforms, including Windows, macOS, and Linux.