MathType is a useful program for writing scientific formula. Everyone can use Math type well because this program is easy to use. Sometimes you get this warning "MathType Requires a Newer Version of MT Extra", you shouldn't be panic about that. You can manually install MT Extra, but you should first remove all the copies already installed on your computer.
Note: Because only one copy of MT Extra will be shown in the Fonts Control Panel at a time, you must refresh your fonts list after deleting each copy of it so that if another copy of MT Extra is in your fonts folder, it will appear. It may be necessary to delete and refresh your list a number of times to delete all copies of MT Extra. If another copy of MT Extra appears in your fonts list, the actual file name for the font will be different.
Download the latest math type here -> Math Type 6.9 and Keymaker
1. Choose Control Panel from the Settings menu of Windows Explorer.
2. Open the Fonts Control Panel.
3. Look for the MT Extra font and delete it.
4. Press F5 to refresh your list of fonts.
5. Look for the MT Extra font again. If it appears, delete it again.
6. Continue steps 3-5 until MT Extra no longer appears in your list of fonts.
7. Open C:\Program Files\MathType \Fonts \TrueType
8. Copy MT Extra and paste into C:\Fonts.
9. Restart your computer and run MathType again, you should not receive
the error again.
Good luck guys