Fortunately, there is a simple workaround : set yourself the right settings / codecs parameters in the textfile of your .prproj
This is how to do it :
1- Find an old of your .prproj that you know is functionnal on your system (a “valid” project)
2- Open it in a text editor (text edit in my case, on mac)
3- In the text editor, locate this words (with the command “cmd-F” on a mac):
MZ.Sequence.PreviewRenderingPresetCodec>
The few lines below this part are the references for codec and preview settings. In my case, they look like this:
EncoderPresets/SequencePreview/795454d9-d3c2-369d-9874-923ab14b7018/P2 1080i-1080p 50Hz DVCPROHD.epr
4- copy those few lines
5- Locate the same spot in the .prproj that you can’t open.
6- Replace the few lines by the ones from your “valid” project
7- Save in the text editor and close it.
8- Open your now “valid”.prproj
This is only a workaround and doesn’t adress the real issue. But still, when you have to meet tight deadlines, it can save the day.