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Ole error coinitialize has not been called

In a project that needed to display HTML documents, I decided to use the TWebBrowser control. I had used this handy ActiveX control successfully in other projects before. This application was an MDI application, written in Delphi 5. As a 'specialty' I had installed a beta version of Internet Explorer on my system. I am not sure which of this is responsible for it, but when I would call the function in my application to display the HTML document, the TWebBrowser element could not be instantiated. Instead I would receive an error message: 'CoInitialize has not been called' The surprising thing is that the webbrowser control shows fine in design mode! I checked and TWebBrowser was properly installed. The underlieing DLL was also registered properly. A call of regsvr32 shdocvw.dll did not help. Finally I manually called the CoInitialize() function. I had to add OLE2 to the list of used units. A good place to do this is the initialization part as the sample snippet below shows. Thanks to Martin Vreeken for pointing out the necessary CoUninitialize() call. Note: In a multithreaded application, you have to put a call to CoInitialize() at the beginning of your thread's Execute method and a matching CoUnInitialize() at its end. uses ActiveX, // <-- make sure to include this unit // older Delphi versions use: OLE2 instead Windows; // and others initialization CoInitialize(nil); // <-- manually call CoInitialize() finalization CoUnInitialize; // <-- free memory end.