This page contains installers for Igor 6.37 (the last version of Igor 6) both Macintosh and Windows versions.
These installers use any valid Igor 6 license key (which is different from the Igor 5 and Igor 7 keys).
Igor 6.37 Installer (22.214.171.124 June 15, 2015)
Windows XP/Vista/7/8/10 (64-bit)
NOTE: Use the 64-bit version of Igor only if you are working with extremely large data sets (or many, many waves) the 32-bit version of Igor is running out of memory, and you can't use Igor 7 (which is 64-bit on both Macintosh and Windows).
See this important ReadMe file about this 64-bit version of Igor 6.37 and the download link for the updater.
Macintosh OS X 10.4 or later
Igor6.dmg (6.37 installer, June 15, 2015)
Revisions made after Igor Pro 6.22A
The files listed on this other page are the most recently built version of Igor Pro (6.38B01) for each supported platform.
(Unlike the installers on this page, these nightly application builds contain only the Igor Pro executable.)