I lost a four year old important Dorico file, but I have the PDF. Stupid question perhaps: is there any way to go from PDF to Dorico?
Not stupid at all. There are a number of programs that do OMR, optical music recognition. You’ll find several threads here on the forum, and a couple of useful reviews on the Scoring Notes website.
None of the programs is perfect; you’ll need to do some amount of correction. But it’s a start.
If it’s one of those crazy ‘modernist’ files that you so often post about, no OMR program on the planet will be able to handle it!
@Janus probably!
At least, the PDF will be a reference to create the document again from scratch.
Do you not have any backups of that file in four years?