Now more and more people choose MathType to edit formulas in documents, because it contains many mathematical symbols and templates, which is very convenient when editing formulas. However, there are also some people who do not use the MathType equation editor when editing equations , and directly use the equation editor that comes with Word to edit. When we need to share a file, this kind of file edited with the built-in formula editor, when we open it on our computer with the MathType formula editor installed, double-clicking the formula does not respond, and they cannot be modified , but it is not realistic to edit the formula again with MathType, so you need to convert the Word formula into a MathType formula.
When using the Convert Equations command that comes with Mathtype to convert the formulas of Word 2007 (and later), an OMML2MML.xsl file is required. This file is available in C:\Program Files (x86)\Microsoft Office\Office12.
Reference: How to convert Word 2010 formulas to MathType formulas