I needed to convert hundreds of documents from Word .doc files to standalone Office Open XML files. The Office Migration Planning Manager includes an Office File Converter utility for bulk conversions but best I can tell, it only produces the zipped docx variety. (See Doug Mahugh’s description). I need to process these with an XSLT file.

After much digging around, I found the PrimaryInteropAssembly redistributable for Office. I figured I could make a simple utility to do the conversion using that. After installing the PIA, it would not show up in the list of .Net assemblies and I was really puzzled until I finally looked in the COM assemblies. Sure enough there it was.

I ended up making a little utility that will open a Word document and save it as whatever type you specify. For multiple files, I just used the FOR command:

FOR %f IN (*.doc) DO WordConvert %f %~nf.xml FlatXML


Releasing the COM objects proved to be harder than I thought. When I first ran the application, (on fifty odd files) I got an instance of WinWord for each time it ran! Eventually had to force garbage collection twice at the end.