"Error initializing VBA components.  APC initialization error: The host object has already been initialized," can appear when loading a Reflection or InfoConnect Desktop Host session.  

This error will appear and either the Reflection Workspace and the Host session user-interface will close, or else the message will appear numerous times, after pressing the OK button, allowing the Reflection Workspace and the Host session to open.  If the user-interface is closed, then the Attachmate.Emulation.Frame.EXE and the R8WIN.EXE or R2WIN.EXE will be "stuck" in memory.

Capturing a Reflection or InfoConnect Workspace.Log file will not indicate what went wrong.  At least two messages will appear in the Windows Event Viewer | Application log for this issue:

Application: Attachmate.Emulation.Frame.exe
Framework Version: v4.0.30319
Description: The process was terminated due to an unhandled exception.
Exception Info: System.AccessViolationException
   at System.Windows.Forms.SafeNativeMethods.MessageBox(System.Runtime.InteropServices.HandleRef, System.String, System.String, Int32)
   at System.Windows.Forms.MessageBox.ShowCore(System.Windows.Forms.IWin32Window, System.String, System.String, System.Windows.Forms.MessageBoxButtons, System.Windows.Forms.MessageBoxIcon, System.Windows.Forms.MessageBoxDefaultButton, System.Windows.Forms.MessageBoxOptions, Boolean)
   at System.Windows.Forms.MessageBox.Show(System.String, System.String)
   at Attachmate.VBA.Engine.ApcDock.Init(System.Windows.Forms.Form, System.Object, System.Object[], Int32)
   at Attachmate.VBA.Engine.VBAController.InitVBA()
   at Attachmate.VBA.Engine.VBAController.ContinueAddingProject(Boolean, Attachmate.Documents.Document)
   at Attachmate.VBA.Engine.VBAController.AddDocumentProject(Attachmate.Documents.DocumentView, Boolean)
   at Attachmate.VBA.Engine.VBAController.DocumentViewOpenedEventSink(System.Object, Attachmate.Documents.DocumentViewEventArgs)
   at Attachmate.Documents.DocumentViewManagerEventHandler.Invoke(System.Object, Attachmate.Documents.DocumentViewEventArgs)
   at Attachmate.Documents.DocumentViewManager.Open(Attachmate.Documents.DocumentView, Attachmate.Documents.ViewVisible)
   at Attachmate.Documents.DocumentViewManager.Open(Attachmate.Documents.Document, Attachmate.Documents.ViewVisible)
   at Attachmate.Reflection.Core.Actions.OpenAction.OpenDocument(System.Uri, Boolean, Boolean)
   at Attachmate.Emulation.Frame.FrameApplication.OpenSpecifiedFilePath(System.String)
   at Attachmate.Emulation.Frame.FrameApplication.HandleSessionFilenameOnCommandLine(System.String)
   at Attachmate.Emulation.Frame.FrameApplication.ProcessCommandLineFilename()
   at Attachmate.Emulation.Frame.FrameApplication.OnContainersStarted()
   at Attachmate.Reflection.Core.CoreApplication.StartContainers()
   at Attachmate.Reflection.Core.CoreApplication.OnLoaderCompleted(System.Object, System.ComponentModel.RunWorkerCompletedEventArgs)
   at Attachmate.Reflection.Core.CoreApplication.Run()
   at Attachmate.Emulation.Frame.FrameApplication.Run()
   at Attachmate.Emulation.Frame.Program.Main()

Faulting application name: Attachmate.Emulation.Frame.exe, version: 17.0.613.0, time stamp: 0x61521e28
Faulting module name: VBEUI.DLL_unloaded, version: 7.1.16.10357, time stamp: 0x5e63686d
Exception code: 0xc0000005
Fault offset: 0x0001701d
Faulting process id: 0x374
Faulting application start time: 0x01d89096cc5e86ab
Faulting application path: C:\\Program Files (x86)\\Micro Focus\\Reflection\\Attachmate.Emulation.Frame.exe
Faulting module path: VBEUI.DLL
Report Id: d708e77d-389a-46ce-89a7-4780096f763a
Faulting package full name: 
Faulting package-relative application ID: 

Full article: https://portal.microfocus.com/s/article/KM000008669