Caddie 9.1 will run on Windows XP, Windows Vista and Windows 7 but only 32 bit versions. Version of operating system later than Windows XP may also change some of the functionality.
Caddie 9.1 will not run on Windows 8
Caddie 9.1 will not run on any operating system that is 64 bit.
It is possible In order to run these (excluding Windows 8) a Virtual OS has to be set up.
There is a FAQ elsewhere that describes how to do this.
Other versions prior to Caddie 15 may also be affected
All versions of Caddie from version 15 will run on 32 bit and 64 bit versions of XP, Vista and Windows 7. Only Caddie 18 is qualified to run on Windows 8