Hello, Apologies if my searching is missing something obvious. I use an industry specific testing device which I upload data to WinXP on my MBA using Parallels 8 previously. Now that I have gone to Sierra and Parallels 12 I can no longer connect to Com1 through the serial port. It states its busy or I do not have permission and will be disconnected. Resolution of this is critical for my nearly every day use. Thanks in advance.