PDF OCR X 2.0 requires Mac OS X 10.7 or higher , and at least 1 gigabyte of RAM. It is compatible with the latest versions of OS X (at the time of writing, this is El Capitain).

If you are still running Leopard (Mac OS X 10.5) or Snow Leopard (Mac OS X 10.6), then you can install PDF OCR X version 1.9, available at http://solutions.weblite.ca/pdfocrx/download.php.

PDF OCR X 2.0 should run on any version of Windows newer than XP (i.e. XP, Vista, 7, 8, 10 etc..) with at least 1 gigabyte of RAM.