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IDProjectCategoryView StatusLast Update
0001684OpenMPTPlugins / VSTpublic2023-04-29 17:55
Reporterdelete12345 Assigned To 
Status closedResolutionno change required 
Platformx64OSWindowsOS Version11
Product VersionOpenMPT / libopenmpt 0.6.9 (upgrade first) 
Summary0001684: Klevgrand VST plugin: Can play FX using VST, but cannot load plugin editor successfully. When loaded, it crashes consistently.

Video recording showing how OpenMPT crashes after loading the VST plugin:

The crash is very consistent. Just by loading a plugin, and then closing the plugin editor window, OpenMPT will always guarantee to crash.

I'm unsure how to obtain error log dumps.

Steps To Reproduce
  1. I used a Klevgrand VST plugin called Speldosa here:

(It is possible to reproduce the error if the VST plugin can be loaded into OpenMPT and play sounds but the plugin editor interface cannot be loaded in OpenMPT properly.)

  1. Load the VST plugin into OpenMPT in a blank new module.
  2. Verify that after loading the VST plugin, you are able to play music using it as an instrument.
  3. Attempt to load the plugin editor.
  4. Observe the plugin editor isn't loaded in properly. I'm unsure how that happens.
  5. After closing the plugin editor window, OpenMPT will become unresponsive and crash subsequently.
Additional Information

I'm only using the Klevgrand VST2 plugin (DLL file).

TagsNo tags attached.
Has the bug occurred in previous versions?Not tested in previous versions
Tested code revision (in case you know it)


Saga Musix

Saga Musix

2023-03-31 17:05

administrator   ~0005639

I installed the latest version of that plugin, and the plugin GUI works fine here. Does it work for you in any other VST host? The plugin changelog mentions that the plugin UI is drawn with OpenGL; it could be a graphics driver issue.



2023-04-01 23:38

reporter   ~0005641

Last edited: 2023-04-02 00:46

Is the latest version v1.0.2? That is the version I'm using right now, and I did check that they haven't put out any other newer versions yet.

For the VST Host, I am able to use Cantabile Lite (a freeware) to load the plugin. I can confirm I'm able to load the plugin GUI normally.

How are you able to load the plugin editor? If you are able to do so, then it points to me doing something incorrect, or different than what you have done. May I ask for your step-by-step instructions of what you have done, so I can check to see if what I did myself had messed up somewhere alone the way? Is there a way that I can read the crash dump from OpenMPT, so I can trace back and see what is wrong on my end?

I can list out the steps I did on my end:

  1. I downloaded the plugin.
  2. I unzipped the ZIP file and extracted the Speldosa.exe installer.
  3. I ran the installer.
  4. I accepted the agreement.
  5. I changed the installation directory to D:\Music\VstPlugin because my C:\ don't have a ton of spaces left.
  6. I made sure to use Custom Installation and install only the 64-bit VST2 plugin (DLL).
  7. I clicked on the "Install" button.
  8. I opened OpenMPT.
  9. I created a new module.
  10. In the "General" tab, I selected the Speldosa plugin after scanning the D:\Music\VstPlugin folder.
  11. And then the rest is what happens in the video linked above.


I noticed OpenMPT didn't crash when I have the plugin editor window opened. So I thought, maybe there is more to this. I went ahead and set the FX1 to Speldosa while the plugin editor is opened, set the instrument to Speldosa, and was able to play notes. Then I thought, maybe the volume knob is clickable in the window, and started playing around with it. I was able to confirm that I can interact with the plugin editor and adjust the volume and reverb (space). I just couldn't see what is being rendered in the window. I don't really know what's going on right now.



2023-04-02 00:04

reporter   ~0005642

capture.png (722,257 bytes)


2023-04-02 06:10

reporter   ~0005643

I'm trying the plugin working just fine

image.png (622,484 bytes)


2023-04-02 06:17

reporter   ~0005644

You can update to development channel to test

Saga Musix

Saga Musix

2023-04-02 11:03

administrator   ~0005645

Yes, I followed the exact same steps as you did, on both 32-bit and 64-bit versions of OpenMPT I now tried it on a second computer and it worked just fine there as well. As you clearly appear to run into rendering issues, I think it would be best if you contact the plugin developer about this. OpenMPT is not involved with rendering the plugin GUI at all, it just provides a window for the plugin to draw into.



2023-04-02 12:14

reporter   ~0005646

Last edited: 2023-04-02 12:30

Ok, I'll get in contact with them. Thank you for looking into this.

By the way, if I'm able to render Speldosa on Cantabile Lite, and it works fine (including rendering and plugin usability), do I still need to contact the developer of the plugin? I'm curious if there is a difference between Cantabile Lite and OpenMPT in terms of how the plugin is rendered in the window.



2023-04-05 22:13

reporter   ~0005651

Last edited: 2023-04-05 22:13

Hi @Saga Musix

After getting in contact with the Klevgrand support team, they asked me to provide them a crash log or a crash dump report that OpenMPT generates. I have no idea where or how to obtain a crash report.

Do you know what the steps are to produce a crash log report?

Saga Musix

Saga Musix

2023-04-05 22:16

administrator   ~0005652

Last edited: 2023-04-05 22:22

Your video does not show a crash - it just shows a hang. You can open task manager, go to detailed view, right-click OpenMPT and choose "create dump file" while it's hanging (DON'T click on "close program"). Note that the file will be very large but 7Z or RAR can compress it rather well. If that's not what the developer wants, you have to ask them how to obtain what they want, I cannot know that.



2023-04-05 23:46

reporter   ~0005653

Thank you. I'll be sure to follow up with Klevgrand. Will keep you posted.



2023-04-29 17:54

reporter   ~0005706

They responded back the following message:


Thank you very much for your respons, and those stack traces!

It looks like it's some sort of issue/conflict with the graphics driver, probably due to OpenGL.

We'll look into solutions to this, but initially it will probably just be some way of turning OpenGL on/off. In the mean time the best workaround would be to just use the v1.0.1 (which would be the same as OpenGL off).

Kind regards,
Mikael /Klevgränd

So in the meantime, I'm sticking with Speldosa v1.0.1.

Saga Musix

Saga Musix

2023-04-29 17:55

administrator   ~0005707

Thanks for the update, I will close this issue then as there is nothing we can do here.

Issue History

Date Modified Username Field Change
2023-03-31 11:06 delete12345 New Issue
2023-03-31 11:08 delete12345 Steps to Reproduce Updated
2023-03-31 11:09 delete12345 Summary Klevgrand VST plugin: Can play FX using VST, but cannot load plugin editor => Klevgrand VST plugin: Can play FX using VST, but cannot load plugin editor successfully. When loaded, it crashes consistently.
2023-03-31 17:05 Saga Musix Note Added: 0005639
2023-04-01 23:38 delete12345 Note Added: 0005641
2023-04-01 23:55 delete12345 Note Edited: 0005641
2023-04-02 00:00 delete12345 Note Edited: 0005641
2023-04-02 00:01 delete12345 Note Edited: 0005641
2023-04-02 00:04 delete12345 Note Added: 0005642
2023-04-02 00:04 delete12345 File Added: capture.png
2023-04-02 00:46 delete12345 Note Edited: 0005641
2023-04-02 06:10 Vad1m_1719 Note Added: 0005643
2023-04-02 06:10 Vad1m_1719 File Added: image.png
2023-04-02 06:17 Vad1m_1719 Note Added: 0005644
2023-04-02 11:03 Saga Musix Note Added: 0005645
2023-04-02 12:14 delete12345 Note Added: 0005646
2023-04-02 12:28 delete12345 Note Edited: 0005646
2023-04-02 12:29 delete12345 Note Edited: 0005646
2023-04-02 12:30 delete12345 Note Edited: 0005646
2023-04-02 12:30 delete12345 Note Edited: 0005646
2023-04-05 22:13 delete12345 Note Added: 0005651
2023-04-05 22:13 delete12345 Note Edited: 0005651
2023-04-05 22:16 Saga Musix Note Added: 0005652
2023-04-05 22:22 Saga Musix Note Edited: 0005652
2023-04-05 23:46 delete12345 Note Added: 0005653
2023-04-29 17:54 delete12345 Note Added: 0005706
2023-04-29 17:55 Saga Musix Note Added: 0005707
2023-04-29 17:55 Saga Musix Status new => closed
2023-04-29 17:55 Saga Musix Resolution open => no change required