https://forums.autodesk.com/t5/inventor-forum/favorites-under-material-library-has-gone-missing/m-p/5593570#M379383 <P>The FavoriteMaterials library is located in the folder C:\Users\&lt;user name&gt;\AppData\Roaming\Autodesk\Inventor 2015 folder. If is not there, it may have been corrupted during the crash. You might check to see if you have a copy from an earlier Inventor version (2013 or 2014) that you can salvage. You may have to migrate it to 2015.</P> Wed, 15 Apr 2015 17:25:02 GMT Anonymous 2015-04-15T17:25:02Z