Can I use the same license for both Windows and Mac?

Yes, for the desktop app. One TaxTron desktop licence works on both Windows and Mac. You don't need a separate licence for each.

• A licence for the new desktop app covers one location on up to two computers, in any mix of Windows and Mac; to move it to another computer, release one of the two first.
• A key for the older (classic) desktop app also works in both its Windows and Mac versions.
• Desktop and Web are separate products: a desktop licence can't be used in TaxTron Web, and a Web licence can't be used in the desktop app.
• Each licence is for one tax year, and a Professional licence is tied to the EFILE number it is first used with.
• If you purchased the wrong one, you can still switch it before use (see "I bought a license but haven't used it yet. Can I switch it?").