https://forums.autodesk.com/t5/inventor-forum/inventor-2015-professional-loses-right-click-and-model-tree-menu/m-p/5799408#M362138 <P>I think I would reformat the hard drive.</P> <P>&nbsp;</P> <P>Install Windows Updates (but not Win 10).</P> <P>&nbsp;</P> <P>Install and run Excel.</P> <P>&nbsp;</P> <P>Temporarily disable anti-virus and UAC and install Inventor.</P> <P>&nbsp;</P> <P>Install Inventor Service Packs and Updates (for your version).</P> <P>&nbsp;</P> <P>Create a Windows Restore Point.</P> <P>&nbsp;</P> <P>This would give you a clean machine and assuming everything is working &nbsp;- a clean restore point from which you can try to diagnose the root cause of the problem.</P> <P>&nbsp;</P> <P>Are you using a 3D Connexion device?</P> <P>&nbsp;</P> <P>I also noted in the picture of your part browser what I would consider "unconventional" modeling techniques. &nbsp;You might attach the *.ipt file here for suggestions on improvements in technique.</P> Wed, 02 Sep 2015 11:30:51 GMT JDMather 2015-09-02T11:30:51Z