Should I install 32-bit or 64-bit versions?

This is not an issue with our latest releases, because only 64-bit versions are installed on Mac, and both 32-bit and 64-bit versions are installed automatically on Windows.

The following applies to our legacy plug-ins (PS5, MRS5, DLG1), whose installers may offer the choice of 32-bit or 64-bit. On Mac OS, both 32-bit and 64-bit versions are installed automatically. On Windows the installer gives you the option to install either or both versions. When in doubt you should install both 32-bit and 64-bit versions. 64-bit versions are needed only if you are running a 64-bit host application. If you are running a 32-bit application on a 64-bit OS then you would still use the 32-bit versions.