Plugin plugin window attach issue

SunshineDreaming · May 19, 2026, 10:33pm

In my own VST3 plugin host (on Windows 10 / 11) already 1800+ plugins load and run successfully.

But there are some plugins, which still refuse to load their plugin window, while succeeding in the SDK VST3 Test Host. One of those plugins for example loads in the SDK Test Host, but in my own host it always terminates, when my host calls plugView->attached() with Access Violation 0x140. The exact same error occurs, if the plugin is loaded with the original editorhost example from the VST3 SDK.

I already contacted their support team and the issue was sent to their development team, but also after more than a month I got no response.

So my questions:

What does the SDK VST3 Test Host do differently than the editorhost sample ?

Are there any interfaces implemented, which I need to support in my own host?

from the logs of my app, when loading the plugin and opening the view for it:

…

VST3 sdkversion = VST 3.7.6

component->initialize (component) returns res=1
PlugProvider: getControllerClassId => controller=1d3cb797d20h 
do plugCtrlBase->initialize(hostContext)
initialize the component with our context  plugCtrlBase->initialize returns res=1  
@PlugProvider::connectComponents
IProcessContextRequirements Icontext_req=1d3cb693c78h
req=0h
preq.wantsContinousTimeSamples=0
setComponentHandler done

controller->createView returns: view=1d3d8a800f0h
IPlugViewContentScaleSupport css=0h
view->getSize() result=0 (0h)
viewRect.origin.x=0 viewRect.origin.y=0 viewRect.size.width=400, viewRect.size.height=100
controller->onShow()
plugView=1d3d8a800f0h
Ausnahme ausgelöst bei [..]  : 0xC0000005: Zugriffsverletzung beim Lesen an Position 0x0000000000000140.

thank you!

Arne_Scheffler · May 21, 2026, 6:50am

Have you set the IPlugFrame on the view via IPlugView::setFrame(IPlugFrame*)?

SunshineDreaming · May 21, 2026, 10:08pm

yes, I have set it as shown in the editorhost example:

github.com/steinbergmedia/vst3_public_sdk

samples/vst-hosting/editorhost/source/editorhost.cpp

0c6df952a


      
          	if (!plugView)
          		return;
          
          	auto platformWindow = window->getNativePlatformWindow ();
          	if (plugView->isPlatformTypeSupported (platformWindow.type) != kResultTrue)
          	{
          		IPlatform::instance ().kill (-1, std::string ("PlugView does not support platform type:") +
          		                                     platformWindow.type);
          	}
          
          	plugView->setFrame (this);
          
          	if (plugView->attached (platformWindow.ptr, platformWindow.type) != kResultTrue)
          	{
          		IPlatform::instance ().kill (-1, "Attaching PlugView failed");
          	}
          }
          
          //------------------------------------------------------------------------
          void WindowController::closePlugView ()
          {

that example causes the same 0x140 exception as my host on that plugin, while the SDK Test Host correctly opens the view of that plugin.

Arne_Scheffler · May 22, 2026, 7:11am

I believe you should contact the plugin developer to inquire about the reason behind the plugin’s crash in the SDK editor host. The editor host serves as the reference implementation, and a plugin should not crash when opened with it.