I am unable to password protect my files. When I hit the security options tab, AutoCAD freezes and becomes unresponsive.I go to the file menu and then hit 'save as'. In this window I go to the top right corner and hit 'tools' followed by 'security options'. Now everything freezes instead of bringing up another window where I can generate a password.Does anyone know what the problem is? AutoCAD is working fine otherwise.I have windows and AutoCAD 2015.Cheers for any help!

Why are you even using the PASSWORD feature in the first place?  Do you share a computer with someone else?  Sounds like a REPAIR of the installation may be in order.  Note that a REPAIR is NOT the same as an UNINSTALL/REINSTALL.  There is no need to go to that extreme.Just curious though.  Have you done any kind of a cleanup on this drawing file?  Run -Purge command?  Run Audit command?  Run Overkill command?
John Connor2015-09-12 22:49:26

The CAD teacher is requiring a password for all files. I have not done a purge, audit or overkill.Could you please tell me how to go about this?thank you

Start with the Overkill command.  You should be in the Drafting and Annotation workspace.  Look on the Home tab > Modify panel for an icon that looks like a broom.OVERKILLRemoves duplicate or overlapping lines, arcs, and polylines. Also, combines partially overlapping or contiguous ones.Next run the command line version of the Purge command.  This is preceded by a dash so it look like this: -purge.Purge Regapps first.  Repeat the command but this time select the All option.PURGERemoves unused items, such as block definitions and layers, from the drawing.Finally, run the Audit command and when AutoCAD asks if you want it to fix any errors it finds answer Yes.AUDITEvaluates the integrity of a drawing and corrects some errors.  It does this by examining the drawing's database.Do a Zoom > Extents then Save your drawing.I'd repeat the entire process a second time just to be sure you did not miss anything.  If you are still having problems with a drawing then we must take further measures.Got all that?  Good.  Now go do it.