No need to struggle anymore. 
There is a new audacity-tools package that can actually recover/rescue many/most of these “broken” projects. See the first post in this thread: Corrupt or Otherwise Broken Audacity Project Recovery
No need to struggle anymore. There is a new audacity-tools package that can actually recover/rescue many/most of these “broken” projects. See the first post in this thread: Corrupt or Otherwise Broken Audacity Project Recovery