Just a wild guess here. The demo version of Finale doesn’t include the Garritan sounds or the software to use them. (Is that what a DSL or a VST is?) Anyway, that may be why they won’t play nicely together; something that’s not in the demo version.

Aha, hadn't thought of that.  Hmm.  Something to ponder.

Thanks,

- John

OK, so, unfortunately, that doesn't seem to be the problem.

I installed my old authorized version of Finale 25 (with Garritan) and I get the same error:

Update: out of desperation, I went back to Windows 10, reinstalled everything.  Result: same error.

If you have a working Finale 27.3 on your computer, I would contact Note Performer. This is probably a conflict with something on your system with NP3. NP3 works very well with Finale 27.3 so there isn't any reason why it should not with yours too. You just need to find the issue. NP may have some tips. You may try this from their site: 

/Library/Application Support/NotePerformer/
Uninstall NotePerformer.command

...and do a complete fresh install. Sometimes Windows can leave stuff behind if you just uninstall and reinstall over and over again.

Unless I'm mistaken, the suggestion of "/Library/Application Support/NotePerformer/
Uninstall NotePerformer.command" from NotePerformer's site is for a Macintosh so that would require quite a bit more than uninstalling Windows...

Hmm, I thought there was a Windows command. At any rate contact NP3 support. They will help.

Remove Finale completely per the following instructions. 

https://makemusic.zendesk.com/hc/en-us/articles/115003352327-Uninstalling-Finale 

Now download and reinstall your purchased version of 25 — make sure that you run both installers in the download. Reboot.

Next reinstall NotePerformer and reboot. See if you still have a problem.

As has been mentioned, the 27 demo does not install the latest Aria Player nor set the paths necessary to run NP. The purchased version will. You may have to reinstall NP again. Arne Wallander is pretty good at troubleshooting this if you get into a bind.

I went a step further and reinstalled Windows 10 completely (this was a new computer build with very little else on it).  Installed Finale 25, including the Aria Player and Garritan.  Installed NotePerformer 3.3.2.  

Finale continues to hang on startup due to being unable to load NotePerformer64.dll.

This is pretty weird.

Does it matter at all that there's another computer in the house using the same internet that is running Windows 10, the Finale 27 Demo and NotePerformer (with no issues at all)?   I can't think why it would, but I figured I'd mention it.

Also, just to enumerate the main differences between this computer and the other:

Computer with functional Finale 27/NotePerformer: i7-7700K, 32GB RAM, Windows 10, GTX 1070, msi 250m pro vd

Computer with nonfunctional Finale 25/NotePerformer: i5-13600K, 32GB RAM, Windows 10, AMD 6700XT,  gigabyte  B660M DS3H DDR4

I've contacted NotePerformer about this but of course email isn't a terribly fast or efficient way to troubleshoot.  

Argh.

Finale continues to hang on startup due to being unable to load NotePerformer64.dll.

I had that exact problem but on a Mac. To make a long story short, the problem turned out to be the hundreds of plug-ins that Finale needed to verify on my system. Why it hung on NP was never explained but Arne provided the solution: Be patient and let it hang till it completes or crashes. If it crashes, try again but do not reinstall NP or it starts over again. It took 4 or 5 times but NP eventually loaded and I didn't have that problem again.

Will this work on your Windows machine? I don't know but you are right about the following:

This is pretty weird.

Well, I've maybe fixed it.

I decided to try and remove my AMD Graphics Driver because of this: https://forums.steinberg.net/t/noteperformer-timeout-on-dorico-4-2-windows/802221/8

So to do that, I had to boot into "safe mode", which I did, but once there I forgot that I hadn't installed the uninstaller program I was supposed to use (https://www.guru3d.com/files-details/display-driver-uninstaller-download.html).

So, I figured, since I'm here, I'll just try running Finale + NotePerformer, and it worked.  I then rebooted into "unsafe" (regular Windows) mode, and ran Finale/NotePerformer and, mirabile dictu, it also worked.

Not sure what to conclude from all this, but hopefully if anyone else has this problem they can discover this saga and perhaps save themselves several days of hardship.

Sincerely,

- John

Safe Mode rebuilds corrupted System paths—same as on the Mac. Sometimes a solution is that simple.

Thanks for posting the follow up.