I have followed Mozilla recommendations for migration, MacRumors recommendations, and others as well. Even the Apple store was unsuccessful. Everything I read suggests that this is straightforward. What am I missing? I have copied my xxx.default file into Profile folder on Mac. Nothing. I have copied my Profile folder in-place of the Mac Profile folder. I have copied the contents of Profile into the Mac profile folder. I have upgraded my PC Thunderbird and then copied the contents of Profile into the Mac Profile. All produce zero data in my Mac inbox. Any thoughts would be most appreciated. Thank you!