Quote - Is there a way to recover the PMD file?

No, once the PMD has invalid info, you're out of luck. You can still save and recover the other settings such as poses and materials.

Turn off saving PMDs.
Delete (or rename) the bugged PMD.
Load scene, save any settings you want to keep.
For each figure, unparent props/hair, delete the  figure, load in a new copy, apply settings and conform any items, reparent props;
Save scene under new name.