MIDI Input Output.dll error on OpenMPT start

[Skaven]

For a few version updates now, I always get this error dialog when I start OpenMPT:



... however everything (at least everything I usually do with OpenMPT) seem to work correctly. The MIDI keyboard works too.

What's weird though, is that the .dll file is actually there! If you explore to the file path, you can find this .dll. For some reason OpenMPT just doesn't find it.

Also, I'm already running OpenMPT 1.22.01.00 in its respective folder, but the .exe seems to search for the .dll in the 1.20.03.00's folder.

[Saga Musix]

Hmm, that's weird. Especially if the file is actually there. MIDI Input Output.dll is OpenMPT's own plugin mostly used for sending MIDI (so the usual "MIDI Record" works without this). When using the installer, it checks if the plugin has been added before (by a previous version of OpenMPT) to the plugin list, and then won't add it again to the plugin list, which is why it still points to the OpenMPT 1.20.03.00 folder.
Try adding said plugin to a song from OpenMPT's plugin selection window. Does that actually work? If the plugin is there but OpenMPT can't "find" it or has trouble loading it, that could also mean that the plugin doesn't find some required dependency, but that would be really weird because it should run on any out of the box Windows installation.
Last but not least, you can simply remove the plugin from OpenMPT's plugin list and the problem should be solved.

[Skaven]

Yep... I tried the "New plugin..." button and found the .dll and added it, but then noticed the earlier .dll was already there.

I can insert the plugin to a slot, but how do I verify it's actually working? At least it's not giving any errors.

Thanks, I'll try just removing the plugin from the list.

[Skaven]

Yup, after removing the old .dll from the plugin list I no longer get the error.

I'm not sure, but because of the way the plugin's path was displayed, it looks like there may have been a space(?) in the file path that may have prevented OpenMPT from finding the file.

[Saga Musix]

I can insert the plugin to a slot, but how do I verify it's actually working?

If it actually loads and the "Edit" button isn't greyed out, there should be no error.

I'm not sure, but because of the way the plugin's path was displayed, it looks like there may have been a space(?) in the file path that may have prevented OpenMPT from finding the file.

I think that just comes from the Message Box trying to resize the text. Can you try adding the old plugin again (be sure the remove the "current" one from OpenMPT 1.22 before that) and check if that also brings up errors? If it doesn't, I have no explanation for this, but at least we know that removing the old plugin from the list works as expected.

[Skaven]

Ok, I tried adding the 1.20.03.00 plugin back to the list, and restarted OpenMPT. There are no error messages.

[Saga Musix]

Ok, that's really weird. I have no possible explanation for that. I guess we should just forget about that one, and if it happens again with a future update, be sure to post here. Maybe there is some deeply hidden bug in the installer or the program itself, but I can't think of anything that would cause such a weird error.

[Skaven]

I haven't actually used the installer... I've just unzipped the zip packages to my Program Files folder. Maybe that explains it?

[Saga Musix]

Hmmm... It might. Since programs (including zip programs and the like) are not supposed to write to the Program Files folder since Vista, there is some weird "compatibility layer" on the Program Files folder which puts all manually modified files (that is, not by a program with administrator rights) into a special folder. I can imagine that this leads to all kinds of problems when mixing programs extracted manually and using installers (like you must have done with the OpenMPT 1.20.03.00 release, since only the installer should automatically add all "built-in" plugins into the list of known plugins, IIRC). I'll try doing something similar (using a zip program and installer side by side) later and see if that explains what has happened.

[Skaven]

I currently have 4 different versions of ModPlug Tracker in their own folders:
"C:\Program Files (x86)\Modplug\OpenMPT-1.22.01.00"
"C:\Program Files (x86)\Modplug\OpenMPT-1.20.03.00"
"C:\Program Files (x86)\Modplug\OpenMPT-1.20.01.00"
"C:\Program Files (x86)\Modplug\OpenMPT-1.19.04.00"

I put them there by just drag&dropping the folder from the zip to the Program Files folder. And then I point my desktop shortcut to the newest .exe. Maybe doing this misses something that the installer does.

[Skaven]

I guess doing the drag & drop won't update the contents of the  C:\Users\<username>\AppData\Roaming\OpenMPT folder?

[Saga Musix]

That's correct, there are no modifications / upgrades done to the config files that way, even when copying over a new version. Did you use the installer at least once, or did you add the MIDI Input / Output plugin to the plugin list manually?