BTW, installing RootsMagic on a Flash drive instead of the Apple FileSystem internal SSD also seems to work around this issue
I just did this with Mac OS High Sierra Beta. Seems to work very well. I had wiped all .plists. RM7 was not playing nice and not opening my datafile completely so I could make changes from FamilySearch. After removing the .plists, the message that RM7 was not optimized for High Sierra and to contact the application provider popped up. I was not going to change the file format on the Solid State Drive in my McBook Pro, so I saw this workaround.
Love it! Thanks, pbooth99.