Welcome to the forum!

The screen shot does not show the entire File Info window.

My guess is that this particular file does not have a file name extension - right?

That could be the explanation why the File Info window says that the file is a “unix executable file”.

If I Recall Correctly, in 1998 there was no file name extension on a Finale document.

An idea:

Try adding the file name extension .mus to the file name.

Then, try to open the old 1998 file.

Could not hurt to try it.

Thank you! Right, no file extension. Good idea about adding .mus but Sibelius would still not open it, (same deal adding ".xml")...can I pay someone to convert them?

… Good idea about adding .mus but Sibelius would still not open it …

Why use Sibelius to open a Finale document?

Why not use Finale?

When it has been opened in Finale, you can export the contents as xml.

* What version of Finale are you using?

By The Way:

Adding the file name extension .xml will not work - since a 1998 Finale document is not in the xml file format.

Actually, no Finale documents are in xml format (not even Finale v27 documents).

Do you have a printed copy? It might be easier to scan it through SmartScore, and get an xml from that.

Thank you! I haven't used Finale for years, I switched to Sibelius around 2000. Yes I have printed .pdfs and will check out smartscore! Thanks

If you like, send me a pdf, and I’ll try it for you. My email is encoded in my signature.

The only way to open a file that old is from within a build of Finale compatible with your Mac. From there, it can be exported to MusicXML. This can be done for 30 days from the Finale 27 demo.

It depends on your version of Sibelius whether you would export as MusicXML 3 or 4 from Finale. The current version of Sibelius requires the free Dolet 8 plug-in to import MusicXML 4. The Dolet 6 plug-in adds support for MusicXML 3 to some older versions of Sibelius.

https://www.musicxml.com/dolet-plugin/dolet-6-plugin-for-sibelius-5-1-and-later/  

The OP sent me a PDF, and I ran it through SmartScore. It took about 15 minutes to run it, and make the few corrections. I sent him the XML. Hopefully, he'll report back here with his results.

Mike did a great job! It opened easily in Sibelius, only requires minimal editing and saved me loads of time, Thanks Mike!