To uninstall iolite v3, but keep Igor Pro on your computer, just go to:
[For PC]: C:\Users\[Your User Home]\My Documents\WaveMetrics\Igor Pro 7 User Files\Igor Procedures
[For Mac]: Applications\Igor Pro 7 Folder\Igor Procedures
and delete any iolite related files there. There should be three shortcut files to delete.
You can then delete the iolite v3 folder from your Program Files folder. Iolite doesn’t make any registry edits during install, so this is all that is required to remove iolite from your system. See the wavemetrics webpage for info on uninstalling Igor Pro.