Because NI no longer offers direct public downloads for legacy versions, obtaining the runtime engine legally requires one of the following:
NI’s Legacy Software Repository (via FTP or direct links)
NI historically provided a public FTP server (ftp.ni.com). Some directories still contain old installers. For example:
ftp://ftp.ni.com/support/labview/runtime/win32/8.5.1/
Note: FTP access may be discontinued; check NI’s current policy.
Installation from Original LabVIEW 8.5.1 Media
The runtime engine installer is typically located on the LabVIEW 8.5.1 installation DVD under \Runtime or as a separate redistributable folder. labview runtime engine 85 1 download hot
Third-Party Archives (Use with extreme caution)
Sites like oldversion.com or academic software archives may host it, but you risk malware. Always verify SHA-256 checksums against known good values if available.
Important: Downloading the runtime engine from unofficial sources without a valid LabVIEW license may violate NI’s EULA. However, the runtime engine itself is redistributable—developers may include it with their applications. For end users, it is generally permissible to download the exact version required by a legitimate application. Because NI no longer offers direct public downloads
Even with the correct runtime, you may face the "hot" frustration of an error 7 or 43. Here is the fix:
Your search string contains clues:
Warning: The urgency of "hot" is exactly what malicious sites exploit. They know you are desperate. They will offer a fake "hot download" that installs adware, keyloggers, or ransomware.