AIMMS Knowledge Base Article – KB000019


Switch version of AIMMS COM object or Excel Add-In



It is possible to switch to a different version of the AIMMS COM object or the Excel Add-In.


When you startup the AIMMS COM object or the AIMMS Excel Add-In, you might get the following error message:

        Incompatible project file


        Could not startup AIMMS

Or any other indication from which you can see that the wrong AIMMS COM object or AIMMS Excel Add-In is started.


During an installation, the latest AIMMS COM object (AimmsCOM.exe in the Bin folder) is registered. When you run the Excel Add-In example, the AIMMS Excel Add-In is registered. Only one AIMMS COM object and one Excel Add-In can be registered at a time (AIMMS 3.5 and lower). For AIMMS 3.6 and higher every AIMMS version has its own AIMMS COM object registered separately.


To use a different AIMMS COM object, you can register that AIMMS COM object

by running the shortcut “Register AIMMSCOM” that can be found in the AIMMS Bin folder.

To use a different AIMMS Excel Add-In, you should

  • (For AIMMS 3.4 or lower) first un-register the current AIMMS Excel Add-In:
  1. Open Excel, in the menu: go to Tools – Add Ins… and uncheck AIMMS Excel Add-In.
  2. Close Excel.
  3. In the registry delete the AIMMS related keys under the following key: “HKEY_CURRENT_USER\Software\Microsoft\Office\9.0\Excel\Add-in Manager”. The AIMMS related keys end with “AIMMS.xla”.

    After that register the new AIMMS Excel Add-In:

  4. Open Excel, in the menu: go to Tools – Add Ins… click on Browse… and select the AIMMS.xla file from the Excel Add-In folder of the corresponding AIMMS version.
  • (For AIMMS 3.5 or higher) run the AIMMS Excel Add-In example in the Examples folder of the corresponding AIMMS version (enable macros). The AIMMS Excel Add-In will be registered automatically.

More information

For more information, please contact us at support@aimms.com.



Last reviewed: 19-12-2005