Hi,
I transferred audio from tape cassette to PC and created an Audacity project. An issue occurred when I opened, edited, then resaved that project.
I still have the audio files in the original folder xx_data. This has 654 .au files in subfolders (e00, d00, d01, e08, d00, d01, d02)
When I open the project xx.aup file it does not connect to the audio files.
I have tried manually importing them into a new project, but they each have to be imported separately and all appear as individual items, unlinked in a project.
Is there a way to get these “orphaned” files into a new project? 
Many thanks for any assistance!
Trevor
Windows 10 64 bit
Audacity 2.1.3
Close Audacity.
Do you get an error message when you double-click the AUP file?
Koz
My wild guess is you closed Audacity or changed the state of the machine before it got done saving the revised AU files. If the AUP Project Manager and the AU files have gotten out of step with each other after an edit, it’s nearly impossible to reconstruct the show.
Koz
Many thanks for your reply.
Yes, there was an error message when I tried to open the aup file, indicating no files available for the project. I think that occurred because I shut down Audacity before the edited project had been fully saved
Very pleased to say that today, for some unknown reason, it can now find the files and I have retrieved the project. The program seems to be self healing! 
That has saved a lot of time!