..application with the same identity is already installed

Unable to install this application because an application with the same identity is already installed
When installing or re-installing the MerlinXL vsto addin you may receive an error message:
Error Message
Unable to install this application because an application with the same identity is already installed. To install this application, either modify the manifest version for this application or uninstall the preexisting application.”

The Microsoft Office Error suggests using Add or Remove programs in the Control Panel, but typically this will already have been done.
This error is probably caused by the Add/Remove Programs operation not removing the items from the registry correctly.


There is already a version of MerlinXL installed

  1. Either check that the COM Addin in Excel is enabled
  2. Uninstall the current version.

Usually a MerlinXL COM addin will automatically update itself is a new version of the addin is placed on the same server that the addin was originally installed from.

Check whether the COM addin is enabled

In Excel check to see if the Merlin tab appears in the Excel ribbon.

If it does and you wish to upgrade then goto the De-install MerlinXL section below, otherwise

Select File | Options | Addin-ins

Select COM- Addins | Go   from the Manage drop down at the bottom of the Options form

In the list of available COM-Addins check the MerlinXL option, then select OK

If the Merlin tab does not appear in the ribbon or MerlinXL is not an available Add-in then goto De-install MerlinXL


De-install MerlinXL

Open Control Panel | Add Remove Programs

If MerlinXL exists, uninstall it by selecting it in the list and then selecting the Uninstall option.

If MerlinXL does not appear as an installed program you need to Clean the Registry

Clean Registry

If it is not there, a previous installation did not uninstall correctly so you need to clear a registry setting.

Open the registry (you will need to have local admin rights)
Delete the registry entries {GUID} relating to MerlinXL
(note it is VSTA not VSTO for some reason)

Additional solutions:
  • Sometimes it may also be necessary to run the following in a cmd.exe window.
    C:> rundll32 dfshim CleanOnlineAppCache


  • Rename the folder 2.0 at the following location. The 2.0 folder will be recreated when you reinstall MerlinXL again. (Note this may affect other VSTO installations)
    •            C:\Users\\AppData\Local\Apps\2.0





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