I'll probably try a reinstall but I'm not impressed with an app I had high hopes for
If you haven't heard of MC until recently I can understand why you might not have high confidence in it. I had literally never heard of the product or company until I started researching players that could play a FLAC file on a Mac. I *almost* didn't try MC because I mistakenly thought the Mac version was "beta" or something. I'm SO GLAD I TRIED IT!
It's been 8 years now and 10 major versions of MC. MC is a VERY solid player. It's arguably the most sophisticated Media player and Library Manager available for Mac. I hope you decide to stick with it. It's capabilities are impressive.
Restarted pc.
You're not running this on a hackintosh are you? I ask because you keep saying "pc". If that's just what you say for "computer" then I understand. But if you're running a hackintosh things might get weird.
Cannot find any trace of previous library meant to be at
/Users/<username>/Library/Application Support/J River/Media Center 19/Library
Media Center version 19 is more than 8 years old. Did you have that installed on this same computer at one time? I don't understand the reference to version 19.
In fact no Library subfolder in Username folder.
Finder hides the Library folder inside your user folder. You can show all hidden files in Finder with <command><shift><period> . Then your Library folder will be visible and you can double click to open it.
I read something in a thread a few days ago that might apply: Some people have had trouble getting version 30 to run unless they installed a previous version (like MC28) first. Try installing and running 28. Then try 30 again.
Here's a link to the last version of MC28 for Mac:
https://yabb.jriver.com/interact/index.php/topic,132366.0.htmlBest of luck.
Brian.