In Microsoft Office Word, the default document template that is used when starting up Word with a blank document is called document.dotm.

I recently accidentially corrupted this file when I was modifying some typography in a document. So I needed to figure out how to restore it.

Turns out it is quite easy. The default document template can be restored by deleting the file:

C:\Users\<username>\AppData\Roaming\Microsoft\Templates\document.dotm

Or:

%APPDATA%\Microsoft\Templates\document.dotm

You can move this file out of the folder or delete it. Then restart Word. Now, it should be restored.

On my system, %APPDATA%\Microsoft\Templates\document.dotm is now checked into Subversion.