Hi! Here is another issue I found: if I use HAPropsSI within circular reference (iterative calculations) on Mac Excel 2011, lots of div/0 errors is showing up (popping up in a message window, not in cells). The same file opened on Windows Excel gives no problems at all.

At first I thought that maybe Excels on Mac and Windows do iterations differently. However, the message window looks like something produced by CoolProp, so maybe you could look into it.

Here is a simple file for testing: file-is-not-available-anymore You might need to switch on iterations.

Best!