An error occurred while saving the commentRichard Lanyon commented
I also have the same problem where you can't open the project by double clicking the file as it stalls and the program crashes.
I am running Catalina on a 2019 16 inch Macbook Pro (2.4 GHz 8-Core Intel Core i9, 32 GB 2667 MHz DDR4, AMD Radeon Pro 5500M 8 GB Intel UHD Graphics 630 1536 MB).
My work around is similar by opening Premiere from the dock, start a new project, then from the menu open the old project which opens fine, then close the new untitled project. This seems to be the only work around which is really frustrating.