https://communities.bentley.com/products/programming/microstation_programming/f/microstation-programming---forum/92081/rename-reference-file-extension-to-dgnI inherited a few 1,000 old MicroStation files with odd extensions &quot;.2d&quot; and &quot;.3d&quot;. :&gt;( We would like to change them all back to &quot;.dgn&quot; for consistency, reduce confusion and so thumbnails work in Windows 7 The problem is that will break all of theen-USTelligent Community 12https://communities.bentley.com/thread/264745?ContentTypeID=1Tue, 29 Oct 2013 21:52:21 GMT6dad98f5-dbc9-4c4d-a9ba-e9da8dc6aa8e:5b93d501-8691-4d28-8f48-1dec234be416RobertArnold<p>Hi,</p> <p>Take a look at:</p> <p><a rel="nofollow" target="_new" href="http://communities.bentley.com/products/microstation/f/273/t/91950.aspx">communities.bentley.com/.../91950.aspx</a></p> <p>Of course in your case, you&#39;d have to replace the Left command with a Right command to look for .2d &amp; .3d</p> <p>--Robert</p><div style="clear:both;"></div>