In this page we have gathered the most common causes of errors and problems you may observe when using VB Migration Partner or when running migrated .NET projects.

1. Did you install all required software components?

When something isn’t working properly – for example, VB Migration Partner stops with a fatal error or generates .NET source files that appear to be truncated – you should double check that all components have been installed correctly and that you are abiding by the terms of the EULA. More specifically, ensure that you have installed the following applications on the computer on which you are attempting the migration:

  • Visual Basic 6
  • All 3rd-party ActiveX controls and type libraries (IMPORTANT: the design-time license for these controls must be installed.)
  • Microsoft Visual Studio (any edition from 2010 onward)
  • VB Migration Partner (!)

You should also ensure that you have registered and activated VB Migration Partner on the computer on which you are attempting the migration. VB Migration Partner must be installed using its companion setup procedure. Just copying the files from a computer to another computer doesn’t work.

2. Did you install the most recent version of VB Migration Partner?

We routinely improve VB Migration Partner by adding new features and fixing bugs. If you notice that VB Migration Partner doesn’t behave as it should, then:

  1. Download the most recent version of VB Migration Partner. (You can easily reach this page by means of the Help-Download upgrades menu command).
  2. Uninstall VB Migration Partner, using Windows’ Control Panel.
  3. Install the new release you just downloaded
vb migration - download upgrades

3. Has your VB Migration Partner license expired?
    [TRIAL EDITION ONLY]

If you notice that your VB Migration Partner Trial Edition is generating truncated .NET source files, odds are that your trial period has expired.

In general, we provide a trial period that is long enough for you to test VB Migration Partner and ascertain that it is able to convert the most critical portions of your VB6 application. By the time when the trial period expires you should be able to reach a decision about purchasing VB Migration Partner.

4. Are you running VB Migration Partner in a virtual machine?

The EULA terms specify that you require the Site License in order to execute VB Migration Partner in a virtual machine. If you find that VB Migration Partner truncates the .NET source files it generates, ensure that VB Migration Partner isn’t running in a virtual machine.

5. Are you running a single instance of VB Migration Partner from a local drive and with administrative privileges?

VB Migration Partner hasn’t been designed in such a way that multiple instances can run at the same time. If you experience random fatal errors, ensure that you aren’t running another instance of VB Migration Partner in the background.

Besides, VB Migration Partner must run under full privileges, therefore you must run it from a local drive and with administrative privileges (or equivalent).

This tip also applies to the VBMP.EXE utility used to perform migrations in batch mode. Please read this article for more information about how to run multiple instances of VB Migration Partner.

6. Does the VB6 project compile and run correctly?

VB Migration Partner requires that all the components that the VB6 projects require – both at compilation time and at runtime – be installed on the computer on which you are attempting the migration. The simplest way to meet this requirement is ensuring that the VB6 project compiles and runs without errors on the computer on which you are attempting the migration.

If you are converting a project group, ensure that it compiles correctly as a whole, by means of the File-Make Project Group menu command in the VB6 IDE.

VB Migration - Make Project Group

7. Have you modified the .NET code after the migration?
    [TRIAL EDITION ONLY]

Here’s the scenario: you have used VB Migration Partner Trial Edition to generate a .NET project; the .NET project runs fine but doesn’t seem to react to keyboard or mouse actions.

The reason for this behavior is that you modified the generated .NET project in ways that aren’t permitted by VB Migration Partner Trial Edition’s EULA. Such unpermitted changes include – but aren’t limited to – adding forms, classes, modules, and structures. When you edit the generated code in this way, all events cease to be fired.

You can easily confirm that events aren’t firing by loading the generated project inside Visual Studio and placing a breakpoint in the method that handles an event that must be fired, for example the handler for the Load event of the main form. If the breakpoint is never encountered, then it’s an evidence that the event isn’t fired.

The only solution for this problem is undoing unpermitted changes or purchasing a full license of VB Migration Partner.

8. Did you check VB Migration Partner’s activity log?

If VB Migration Partner isn’t working correctly, check its Activity Log window, which reports both informational and error messages emitted during the migration process. (Error messages are can be easily spotted because they are tagged with a red icon.)

VB Migration - Activity Log

In most cases, the error messages in this window are self-explanatory and can reveal the cause of the malfunctioning and its solution.

9. Are you running the .NET project on the same computer where you migrated it?

In some cases, the .NET project created by VB Migration Partner depends on one or more COM components. The list of these COM components includes:

  • The following ActiveX MSDATGRD.OCX, MSHFLXGD.OCX, MSCHRT20.OCX, MCI32.OCX, MSCAL.OCX, MSWINSCK.OCX (if referenced by the original VB6 project)
  • The following type libraries: DAO.dll, InetCtlsObjects.dll, MSCommLib.dll, msdatasrc.dll, MSMAPI.dll, MSScriptControl.dll, RDO.dll (if referenced by the original VB6 project)
  • The VBSupportLib.dll and the msvbvm60.dll file – only if the original VB6 project uses the Printer object, the Print common dialog, or the Winsock control

If the generated .NET project works well on the computer where VB Migration Partner is installed but not on another computer, make it sure that you correctly installed and registered the COM components.

10. Did you search VB Migration Partner’s knowledge base?

Half the queries our tech support team receives could be solved by simply searching our ever-growing knowledge base. As of this writing, there are over 250 distinct KB articles available on our web site, and we add new articles virtually each day.

If you experience a weird behavior – either during the migration or when running the migrated .NET project – your first step should be searching our documentation by means of our Google-powered search engine. In most cases, it’s just a matter of typing the right search keyword. Here are some hints:

  • If you have a compilation error or a runtime exception, search for the error’s message
  • If you have problems with a control, component or method, search for the control or method’s name (e.g. “TextBox” or “MsgBox”)
  • If the migrated .NET project doesn’t behave exactly like the original VB6 code, try searching for “minor differences” or “equivalence”

Please notice that the knowledge base you can search online is the same KB that our tech support team queries when one of our customers submits a query. By searching the KB yourself, you can often save both your and our time, and solve the problem in a matter of minutes.

11. Did you correctly install all ActiveX controls and type libraries?

If VB Migration Partner’s Activity Log window includes one or more messages that read “Unable to convert XXXX type library” (or similar), then you should check that

  • All the ActiveX controls and type libraries have been correctly installed on the computer on which you are attempting the migration. (In doubt, use the RegSvr32 utility to reinstall them.)
  • The major and minor version number of the control/typelib is the same among all the VB6 projects being migrated.
  • Their path matches the path found in the .vbp file of the VB6 project being converted.

IMPORTANT: it is essential that you have installed the design-time license of all the ActiveX controls used by the application being migrated; installing just the runtime license isn’t enough. The easiest way to check that you have installed the design-time license is loading the VB6 project inside the VB6 IDE and compiling it.

In most cases, VB Migration Partner is able to convert VB6 projects even if their .vbp file contains one or more invalid paths, yet in some circumstances VB Migration Partner may fail to guess it correctly. If in doubt, just reload the VB6 project inside the VB6 IDE, make a minor edit to any source file (for example, insert a space at the end of a code line), and then save the project: this action typically forces the VB6 IDE to re-evaluate the correct path for all controls and type libraries.

12. Did you update the original Visual Basic project to VB6?

Some VB6 business applications were initially coded in VB4 or VB5. In some cases, these applications – or at least some of their constituent projects – were just recompiled under VB6 but were never really converted to VB6 and their source files still contain leftovers from VB4 or VB5, for example attributes that VB6 doesn’t support any longer. These attributes are hidden and aren’t visible from inside the VB6 IDE, yet they can prevent VB Migration Partner from correctly migrating the application.

If you suspect that your VB6 project is still using unsupported hidden attributes, just follow this procedure:

  1. Load the project inside the VB6 IDE
  2. Make a minor change to eachsource file in the project (Tip: you can just add an empty line at the end of the file)
  3. Save the entire project

13. Did you clear VB Migration Partner’s type library cache?

VB Migration Partner creates a special area on your hard disk, known as type library cache. This area is used to store the result of the analysis of ActiveX controls and type libraries used by the project being migrated, so that subsequent migrations can run faster.

In some cases, however, the Type Library Cache may become out-of-sync and you should clear it and start again with an empty cache. The easiest way to clean it up is enabling the “Clear type library cache when VB Migration Partner starts” option, in the General tab of the Tools-Options dialog box, then closing and restarting VB Migration Partner.

VB Migration - Clear library cache

After you have cleaned up the type library cache, you might want to disable that option, so that subsequent migrations can run as fast as possible.

14. Did you insert your pragmas correctly?

VB Migration Partner’s pragmas are just special VB6 remarks. As such, they should be inserted only where a VB6 remark can be inserted. For example:

  • You cannot insert a pragma at the very top of a VB6 file, because the first line is usually reserved by VB6 to identify the file type (form, class, module, etc.)
  • You cannot insert a pragma inside a form or UserControl’s definition area – i.e. the area in the .frm or .ctl file used to define the form and its controls’ properties.
  • You cannot insert a pragma in the middle of multiline VB6 statement.

If you are in doubt, just insert the pragma from inside the VB6 IDE instead of using VB Migration Partner’s integrated code editor. The sequence for doing so is quite simple:

  1. build the pragma using VB Migration Partner’s Edit-Insert Pragma menu command
  2. click the Copy button to copy the pragma’s text in the clipboard
  3. switch to the VB6 IDE and paste the pragma where appropriate

Also, keep in mind that if a pragma has an incorrect syntax you should find an error message in the Activity Log window, at the end of the migration process.

15. Did you run the “Explain Errors and Warnings” command?

If the migration completed correctly but you are puzzled by the many error and warnings messages found in VB Migration Partner’s lower pane, you should run the Tools-Explain Errors and Warnings menu command. This command brings you to a page that summarizes and explains all the messages in your migrated code and recommends a strategy to solve them.

You need an active Internet connection to run this command.

VB Migration - Explain Errors ans Warnings

16. Are you annoyed by the “One or more compiled files of the selected solution aren’t up-to-date with the source code” message?

When you start a conversion, VB Migration Partner compares the timestamp of the VB6 executable file – be it an EXE, DLL, or OCX file – with the timestamp of all the source files that are part of the project being migrated. If any source file is newer than the executable file, VB Migration Partner displays the dialog box in question.

VB Migration - Out of date VB6 project

Some users complain that this dialog box appears even if they have compiled the VB6 project from inside the VB6 IDE, an action that is supposed to save all files before the actual compilation takes places. However, this isn’t correct, because the VB6 IDE compiles the source files in memory, without having to save them to disk.

Additionally, in some cases the compilation process flags the VBP file as “dirty”, therefore this file is automatically updated when you exit the VB6 IDE or you issue the File-Save Project menu command. As a result, the VBP file appears to be newer than the executable file.

The only way to ensure that all VB6 source files are up-to-date is

  1. Edit all VB6 source files as required
  2. Use the File-Save Project menu command to save all edits to disk
  3. Compile the VB6 project or project group from inside the VB6 IDE
  4. Exit the VB6 IDE – if a dialog box appears and informs you that the VBP file needs to be saved then cancel the exit operation and repeat steps 2-3-4.

17. Did you create a sample project that reproduces the problem?

If you are trying to solve a problem that occurs either during the migration process or when you run the migrated .NET project, it is essential that you provide a self-contained VB6 sample project that allows our tech support team to reproduce the issue. Without such a sample project we might unable to work on your problem and offer you the solution.

We understand that creating a sample project can take some time; however, please bear in mind that if you don’t prepare such a sample project, we have to do it anyway, and we might not have enough information to create the sample and reproduce the problem.

Also, if preparing the sample requires time, we must give your request a lower priority, so that we can focus on other requests that were accompanied by a complete sample.

When preparing a complete sample, remember to include:

  • A complete VB6 project that reproduces the error
  • All the 3rd-party libraries that are referenced by the VB6 project. (You don’t need to send libraries that come with VB6 or with Windows, e.g. DAO and ADODB libraries.)
  • All the 3rd-party controls that are used by the VB6 project.
  • The .NET project you obtained from VB Migration Partner (if the problem occurs at runtime).
  • An exhaustive description of how to reproduce the problem (if the problem occurs at runtime).

Please help us provide you the best tech support.