Like all well-behaved Windows programs, Metafile Companion registers itself for certain file types only if no other program is already registered for these file types. It is up to the registered program to offer a way to unregister itself.

For example, if you run the command:

metacomp /?

(from the folder where Metafile Companion is installed) to view the command line options for Metafile Companion, you will see two registration options:

/Register

/Unregister

So to unregister Metafile Companion, you would run the command:

metacomp /Unregister

So if some other program is registered for a given file type (e.g. .WMF), you should see if the registered program offers an “unregister” option.

Once the other program is unregistered, you can run the command:

metacomp /Register

to register it.

Another way to associate a program with a file extension is using the Windows Explorer:

  1. Run Windows Explorer to navigate to a file of the desired type (e.g. “test.wmf”).
  2. Right-click on the file and choose “Open with” > “Choose default program…”
  3. Select the program that you want to edit the file (e.g. “Metafile Companion”)
  4. Make sure “Always use the selected program to open this kind of file” is checked
  5. Press OK to save the new settings.

It is possible to hack at the Windows Registry to undo the registration for a program, but this is fairly advanced. Basically, you would use the Windows RegEdit program to go to the key:

HKEY_CLASSES_ROOT\.wmf

and set the “Default” value data to “MetafileCompanion32.WindowsMetafile”. This assumes that the “HKEY_CLASSES_ROOT\MetafileCompanion32.WindowsMetafile” key exists and is set up properly.

If Metafile Companion is registered properly, then Windows OLE Container applications like Microsoft Word can insert a metafile inside a document with the Insert > Object… > Create From File command. Once a metafile is placed inside a document as an object, editing it will call up Metafile Companion as the in-place editor.

 

Also, I assume you are running from an account with Administrator privileges. If not, then Metafile Companion cannot fully register itself. Metafile Companion tests access to the registry key “HKEY_CLASSES_ROOT\MFCOServ.Document” to see if it can register its OLE server.

 

Just for anyone else having this issue: The following did solve the problem for me.

It is possible to hack at the Windows Registry to undo the registration for a program, but this is fairly advanced. Basically, you would use the Windows RegEdit program to go to the key:

HKEY_CLASSES_ROOT\.wmf

and set the “Default” value data to “MetafileCompanion32.WindowsMetafile”. This assumes that the “HKEY_CLASSES_ROOT\MetafileCompanion32.WindowsMetafile” key exists and is set up properly.