CAD tip # 8214:

If you have installed Express Tools but after some subsequent modifications and changes in the user environment, the tools menu (ribbon) is no more available or the individual tool commands cannot be invoked, try any of the following remedial actions.

• With the APPLOAD command, load these two FAS files: acettest.fas and acetutil.fas; both should be located in the Express subfolder in your AutoCAD folder
• Use CUILOAD to load the possibly missing menu file acetmain - e.g.: C:\Users\yourname\AppData\Roaming\Autodesk\AutoCAD Electrical 2012\R18.2\enu\Support\acetmain.cuix
• Add the Express Tools path to your AutoCAD search path - e.g. C:\Program Files\Autodesk\AutoCAD 2013\Express
• Enter the EXPRESSTOOLS command (even this simple step helps in some situations)