If you have a 64-bit Windows system, you can install ENVI in two modes: 64-bit and 32-bit. The 64-bit Windows installer includes both modes, so you don't need to download separate files. The 32-bit mode is useful if you want to use ENVI with ArcGIS, which requires 32-bit compatibility. To launch ENVI in 32-bit mode, follow these steps:
Click on the Windows Start menu.
Find the ENVI x.x folder, where x.x is the software version.
Click on ENVI x.x (32-bit) to start the program.