Author Topic: "Invalid serial number" error on Windows Vista/Windows 7  (Read 2947 times)


  • Kindly Curmudgeon
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"Invalid serial number" error on Windows Vista/Windows 7
« on: February 23, 2011, 01:41:24 PM »
Sometimes on Windows Vista or Windows 7, users run into this problem:
When they try to run DesignCAD, it complains that the serial number is invalid. If the user selects "Run as Administrator" however, it runs normally.


(WARNING: This involves making changes to the registry. Although we have done this change several times without mishap, anytime one edits the registry there is the potential for disaster. You may want to do full system backup before proceeding.)

Start/Run “regedit”  (May need to do this as Administrator, or give Admin permissons to run Regedit)

In the left column of RegEdit, do Ctrl-Home or manually highlight “Computer” at the top of the list.

Edit/Find “VirtualStore”

This should locate the VirtualStore folder in HKEY_CLASSES_ROOT.

Expand VirtualStore to show MACHINE


Look for IMSIDesign (may be an empty folder) inside the SOFTWARE category.  (Note: for 64-bit systems, you may have to expand the Wow6432Node folder.) IF YOU FIND AN IMSIDESIGN FOLDER ANYWHERE ELSE OTHER THAN INSIDE THE VIRTUALSTORE/MACHINE/SOFTWARE FOLDER, LEAVE IT AS IT IS.

Right-click on IMSIDesign (again, ONLY inside the VirtualStore portion of the registry) and select “Delete”. (Or if you are feeling cautious, choose “Rename” and give it a different name such as IMSIDESIGN_0).


Now try starting DesignCAD without the “Run as Administrator” flag. If it runs normally, mission accomplished!

25 years with DesignCAD