I was able to finally migrate my Quicken Mac 2007 data file to Quicken 2019 (thanks to Quicken technical support) by "save a copy" into a folder on the desktop, and this imported fine. All other methods failed to import.
I could not "save a copy" on High Sierra (due I think to the APFS drive format). I used an old laptop with El Capitan (and HFS+ drive format) to do the "save a copy" which was what worked for me. You may need to do the same. But I would call a tech support person at Intuit; they were very helpful.
This is all well and good, but when I try to safe a copy of my Quicken 2007 file I get the error message "Unable to erase partly copied files" and it aborts the file creation effort. I get a couple folders, but no copy is created. I can create a back file .qdfm. Is creating copy or creating a backup result in the same .qdfm file creation? I just want to make sure I can update from Quicken 2007 for Mac into the Quicken 2019 before I commit to invest into updating my SW. I am running MacOS Mojave v10.14.2.