C:\Program Files (x86)\ProMash (from 64-bit system)
If you have made a bunch of customizations and saved them they are probably in these files. You can back the files up by copying them someplace else. Occasionally people will update these files (with newer grains and hops, BJCP updates, etc.) and make them widely available. If you have downloaded the newer files to your computer it is easy to update your ProMash. Copy the new DAT files into the folder and allow them to overwrite the older DAT files.The black arrows point to where your recipes and brew sessions are stored. This can also be helpful for backing up your files, and when migrating to a new computer. Those recipe files are easy to email to others as well. Just find your corresponding .rec file.