The macros must be enabled. If your experience problems running the sizing tools you probably need to enable the macros in your excel preferences. The procedure to enable them can be different according to the excel version you are using, but it's not difficult to find the appropriate procedure on the internet searching the words "enable macro" and your excel version (for example, you can search on your favorite search engine: "enable macro excel 2010").
The operation of the sizing tools is not guaranteed with alternative software like OpenOffice or LibreOffice.
OMI sizing tools are quite similar to one another, but some features may change. If you need support on operating a specific sizing tool please contact our sales department.