https://forums.autodesk.com/t5/navisworks-forum/manage-clash-detection-results-tab-column-sorting-issue/m-p/5687113#M19036 My guess is something happened to the file that contains the grid. Can you attach a previous version of that file ? Mon, 22 Jun 2015 06:11:07 GMT Patrick_Aps_9121 2015-06-22T06:11:07Z