I have files created by InStat Mac version 2, but InStat 3 will not open them.

InStat 2 for the Mac created files in a unique format that cannot be read by newer versions of InStat. Sorry. The only way to move data from InStat 2 Mac to InStat 3 is to open the file with InStat 2, and then copy and paste the data to InStat 3. Or export the data as a text file, and import into InStat 3.

InStat 2 for DOS saved files in a different format than used by the Mac version, so InStat 2 (DOS) files can be opened by either the Windows or Mac versions of InStat 3.

If you don't already have a copy of InStat Mac version 2, download it now. The password to unstuff is "view". It won't ask for a serial number.

InStat 2 was written long before OSX existed. Current releases of OSX won't even allow OS9 (or classic mode) to work, so you'll need to find an old mac computer.