Stop warning whenever any Building Block is used
Since Version 1908 whenever a building block is used or the Building Block Organizer is accessed this loads Building Blocks.dotx and changes the saved state to false. This triggers a warning message when leaving Word asking whether the user wants to save changes to Building Blocks.dotx, even when there have been no changes.
See this thread in the Answers forum.
Charles Kenyon commented
Seems to be fixed in Version 2002 (Insiders Fast Track).