Due to its age, National Instruments has moved LabVIEW 8.5.1 to their section. You will NOT find it on the main NI Downloads page after 2021 without a direct link.
Although newer versions of the LabVIEW Runtime Engine are available, there are several reasons why you might need to download version 8.5.1 in 2021: labview runtime engine 85 1 download 2021
| Error Message | Cause | Fix | |---------------|--------|------| | “Error 7: Out of memory” | 64-bit Windows conflict | Run your LabVIEW .exe in Windows 7 compatibility mode. | | “Missing MSCRT90.dll” | Missing Visual C++ 2008 Redistributable | Download and install vcredist_x86 2008 SP1 from Microsoft. | | “NI VISA not found” | Your app needs VISA drivers | Download NI-VISA 5.4 (legacy compatible) from NI archives. | | Installer hangs at 95% | Windows Defender interfering | Temporarily disable Real-time protection. | | “This app can’t run on your PC” | Trying to install 64-bit version (doesn’t exist) | Redownload the 32-bit .exe (the only version). | Due to its age, National Instruments has moved LabVIEW 8