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COM Add-IN :Interface not registered RRS feed

  • Question

  • Hello Team,

    We have developed a COM Add-In in MS Excel 2019 which is used by a desktop application based on WPF (C#).

    Excel 2019 gets launched from the application (WPF ,C#) which intern loads the Excel add-in fetch data from WCF service and populates those in the Excel.

    At the moment, when the application tries to launch Excel it throws the below exception.

    [2019/09/24 19:02:51:068] PID[10068] ThreadId[10] [FATAL] – [****] Exception Log Details.... 9/24/2019 7:02:51 PM
    Date Time : 9/24/2019 7:02:51 PM ,
    NameSpace : Microsoft.Office.Core ,
    Class Name : Microsoft.Office.Core.COMAddIns ,
    Method Name : Item ,
    Exception Message : Interface not registered

    Failed to find proxy registration for IID: {000C033A-0000-0000-C000-000000000046}. ,
    Error Trace :    at Microsoft.Office.Core.COMAddIns.Item(Object& Index)
       at EZI.ADTool.CalibrationSheet.Generation.ExcelProcess.ExcelAddinInfo() 
    Inner Exception:  

    This functionality works well till office 2016 (32-bit version ).

    After spending days in investigating this we found the below entries in registries of the machine where it's not working Excel (Excel 2019 32-bit version, OS Windows 10 64-bit):

    Registry Entries :
    Computer\HKEY_CLASSES_ROOT\WOW6432Node\Interface\{000C033A-0000-0000-C000-000000000046}
    Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Classes\WOW6432Node\Interface\{000C033A-0000-0000-C000-000000000046}

    Computer\HKEY_CLASSES_ROOT\Interface\{000C033A-0000-0000-C000-000000000046}

    So, this machine (Excel 2019 32-bit version,OS Windows 10 64-bit) has  the three entries for the same clsID

    Registry entry of the machine where it's working (Excel 201632-bit version,OS Windows 10 64-bit):

    Registry Entries :
    Computer\HKEY_CLASSES_ROOT\WOW6432Node\Interface\{000C033A-0000-0000-C000-000000000046}
    Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Classes\WOW6432Node\Interface\{000C033A-0000-0000-C000-000000000046}

    So, this machine (Excel 2016 32-bit version, OS Windows 10 64-bit) has  the only two entries for the same clsID.

    So, removed the Extra/invalid  entry at the path "Computer\HKEY_CLASSES_ROOT\WOW6432Node\Interface\{000C033A-0000-0000-C000-000000000046}" and it works fine now.

    But we never created this entry manually.. Is it a defect  in MS Excel 2019 or is it safe to remove this entry ?

    OFFICE 2019 Version details are attached as image.

    Please help me in getting through this issue.

    Happy Programming !!!


    Regards,

    Hemant

    Wednesday, September 25, 2019 7:38 AM