My son gave me a mid 2010 iMac which I did a clean install of High Sierra on and completed all the updates. I then proceeded to install WSJT-X, Grid Tracker and Fldigi. WSJT-X worked great after the terminal commands were made, Grid Tracker is flawless and Fldigi is a crash monger... I get the message "Fldigi-4.1.20 quit unexpectedly." when launching. I have followed the directions as outlined in K3DCW's sticky message, but there are no pref files to be found because the app never successfully launched. I will greatly appreciate any suggestions for a solution. My intention is to use this computer with my FT-818nd and SignaLink USB for VHF. That combo and WSJT-X works great on HF and my first contact was a station in Utah (20 meters FT8) on 3 watts. 73 de KØGMK
Do you have the High Sierra-specific version of Fldigi? https://sourceforge.net/projects/fldigi/files/fldigi/fldigi-4.1.20_hs.dmg/download
Are you on the LINUXHAM mailing list on Groups.IO, where the Fldigi developers hang out and where they provide the best support for Fldigi on linux AND macOS? If not, post your issue there and I bet you'll have an answer much more quickly than you will here.
Glad to hear it. The team of developers and support people on that list are fantastic, and Cliff is always one of the best of the bunch.