Can I use one license on two Macs at the same time?

Yes. One license can remain activated and be used on up to two Macs you own or control at the same time. To move it to a new Mac, deactivate the license on an existing Mac in Preferences → License, then activate it on the new Mac. Deactivating needs an internet connection. If the old Mac was lost or no longer works, you can release it yourself: open View Order in your purchase receipt email, open the license, and click Deactivate next to that Mac under Activations. Tell the Macs apart by activation date, or by the code labeled “This Mac's code” in Preferences → License on the Mac you still use. If that doesn't work, email support@slipsound.com from your purchase email address.