A change was made to the English energy unit string from "Btu" to "BTU" used in defining ranges in Chemics.  If an "old" Chemics file is opened you might get an error message stating that the Chemics file is "invalid" and there was an "invalid unit string specified for chemics.range object".


To fix this, open your Chemics file (*.chmx) in a text editor and change all "Btu" to "BTU".