Ok, so sometime we do stupid things, with that in mind in an effort to save hard disk space i relocated my catalog library onto a separate hard drive. Once I did that I was unable to view the files, so now im trying to bring it back and I can't get it back. Help!
Did you move the Content Browser Library (for example, my ACA 2015 library is at C:\Users\David\Documents\Autodesk\My Content Browser Library\ACA 2015\ContentBrowserLibrary.cbl)? Or did you move the files associated with the individual catalogs that were loaded into your Content Browser?
If you just want to get things back to the way that they were when the software was installed you can do a Repair or Reinstall on your software. That should reinstall "missing" content and fix the pathing to point back to the content. It will also get rid of any customization to menus, etc so beware of that.
To do this, open the control panel -> select Uninstall a Program -> select AutoCAD MEP 201x -> select Uninstall/Change -> select Repair or Reinstall and select Repair. Reboot your computer and then retest the software. If the Repair doesn't work, then try the Reinstall.