Unable to cast COM object of type 'microsoft.Office.Interop.Excel.ApplicationClass' to 'microsoft.Office.Interop.Excel.Application'"

Question

I am attempting to capture some data from Excel from within a C# console application.

I get the error

Unable to cast COM object of type 'microsoft.Office.Interop.Excel.ApplicationClass' to 'microsoft.Office.Interop.Excel.Application'"

This code used the 'Microsoft Excel 12.0 Object Library', and I included a reference to 'Microsoft.Office.Interop.Excel'.

I dug a little bit this site and came across Interop type cannot be embedded, but I could not understand it enough to implement what was suggested as a solution.

My .NET version is 4.5.

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;

using Excel = Microsoft.Office.Interop.Excel;

namespace deneme
{
class Program
{
    static void Main(string[] args)
    {

        Excel.Application xlApp = new Excel.Application();
        xlApp.Visible = true; // <-- excel application
        xlApp.DisplayAlerts = false;

        // Open the workbook.
        Excel.Workbook wBook = xlApp.Workbooks.Open("C:\\FNN\\XLA\\fnnComTemplate.xlsx",
            Type.Missing, Type.Missing, Type.Missing, Type.Missing,
            Type.Missing, Type.Missing, Type.Missing, Type.Missing,
            Type.Missing, Type.Missing, Type.Missing, Type.Missing,
            Type.Missing, Type.Missing);

        // get the sheet
        Excel.Worksheet wSheet = wBook.Sheets[0];
        // foreach (Excel.Worksheet sheet in wBook.Sheets) { if (sheet.Name == "templateSheet") { wSheet = sheet; } }

        Excel.Range rng = wSheet.get_Range("A1");

        aux = wSheet.Range["F6"].Value;

        Console.WriteLine("interop result:" + aux);
        Console.ReadLine();

    }

}
}

http://www.codeproject.com/Tips/801032/Csharp-How-To-Read-xlsx-Excel-File-With-Lines-of — Amit, Jan 21 '15 at 12:08
See [here](http://blogs.msdn.com/b/dau-blog/archive/2012/04/20/how-to-solve-unable-to-cast-com-object-of-type-microsoft-office-interop-excel-applicationclass-to-interface-type-microsoft-office-interop-excel-application.aspx). — Patrick Hofman, Jan 21 '15 at 12:39

score 74 · Answer 1 · edited Oct 21 '22 at 18:31

74

For Microsoft Office 365 in Windows 10

I was running Microsoft Office 365 with Windows 10 and tried the mentioned solutions to remove the registry key without success.

I went to Settings -> Apps in an attempt to repair the Office 365 suite:

To get there you can follow these steps:

Open Start
Select Settings
Select Apps
In the default page, Apps & features, search for Microsoft 365
Select "Microsoft 365"
Select "Modify"

I selected the Quick Repair option:

This resolved the issue for me.

edited Oct 21 '22 at 18:31

TylerH

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answered Nov 07 '17 at 19:18

Alex

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2

The quick repair helped me (but it was at least 5 minutes). Make sure you look for "Microsoft 365 Apps" in "Add or remove programs" and not for "Office", else you will repair the wrong office. Originally I installed office365 while keeping the old office. At one point the windows started to use the old office, I set again to use the new one, but then I had this error. – Istvan Heckl Mar 01 '22 at 07:11
I kept repairing an Application named "Microsoft 365 (Office)" and it was doing nothing. I finally slowed down and looked again and there is also an app named "Microsoft Office 365 -en-us. Doing a repair here did take a few minutes but resolved the issue. – greg Apr 17 '23 at 15:12

score 44 · Accepted Answer · edited Oct 21 '22 at 18:34

44

If this is not a code-related error, then please remove the registry key listed below. This issue is caused by the key being left over from a higher version of Office.

Steps:

Go to Start
Select Run
Type regedit and hit Enter
Navigate to HKEY_CLASSES_ROOT -> TypeLib -> {00020813-0000-0000-C000-000000000046} -> 1.9/1.8/1.7
Delete the registry key

edited Oct 21 '22 at 18:34

TylerH

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answered Jan 21 '15 at 12:33

Jayesh Goyani

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Please explain what problem you perceived from OP's question, what deleting this registry key does, why you think that will solve OP's problem and where you found this solution. – CodeCaster Jan 21 '15 at 12:46
In case you have Office2016 and unable to get interop to work you need tzo install Off2013. The you need to delete this reg. key to get office interop to work. In case you don't have office interop instal nuget package https://www.nuget.org/packages/Microsoft.Office.Interop.Excel/ – OSP Aug 03 '16 at 10:22
2

Old question, I know but: Cool! You just saved us a lot of time! Just to add, this also might happen when you move from 64 bit to 32 bit. This works because apparently the office interop is trying to use the highest version and/or 64 bit if available. If there is a path in this key that does not exist, it will give this error. So if the office version is uninstalled but the key is still there, it fails when looking up the path! – rperz86 Feb 21 '20 at 13:37

score 10 · Answer 3 · edited Oct 21 '22 at 18:35

10

A simple repair of Microsoft Office resolved the issue for me.

edited Oct 21 '22 at 18:35

TylerH

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answered Sep 28 '17 at 11:42

hawbsl

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I've done this and it work ! – Florence Dec 05 '22 at 08:02

score 2 · Answer 4 · edited Feb 04 '16 at 14:49

A machine had been updated to Office 2016 64-bit and the COM interface was throwing exceptions when called from the a 32-bit application. It did not have old TypeLib entries like the ones in Jayesh's answer.

Comparing ProcessMonitor traces to a working machine with Office 2016 led to what look like dead end registry keys in

HKEY_CLASSES_ROOT\Wow6432Node\TypeLib\{00024..

The working machine would check for the non-existent registry key and return

NAME NOT FOUND

The failing machine had the registry key but then would throw an exception shortly thereafter.

After repeatedly deleting the registry key, rerunning the trace, deleting the next failing key, the COM interface functionality was restored.

Stathis Agrapidis · Answer 5 · 2018-08-24T10:58:12.587

Using the exact same code I got the same problem in a laptop when everything worked fine on another one. I tried various solutions found here and there in the internet but what finally worked, was the explicit definition of the use of non 32 bit version of the library. For doing so in visual studio, I had to tick and then untick the box "Prefer 32-bit" in the build section of the project configuration, which added <Prefer32Bit>false</Prefer32Bit> in the .csproj file.

score 1 · Answer 6 · edited Oct 21 '22 at 20:45

1

I had this issue in PowerShell. Along with the mentioned issue, $xlApp.Workbooks returned null for me. Running the PowerShell script in 32-bit mode resolved my issue.

edited Oct 21 '22 at 20:45

TylerH

20,799
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answered Jan 23 '21 at 06:07

meir

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score 1 · Answer 7 · edited Oct 21 '22 at 18:42

My setup: Visual Studio: 2019, Office: 2019 x64, Target Framework: net5.0-windows

Nothing help me from error:

Unable to cast COM object of type 'System.__ComObject' to interface type 'Microsoft.Office.Interop.Excel.Application'. This operation failed because the QueryInterface call on the COM component for the interface with IID '{000208D5-0000-0000-C000-000000000046}' failed due to the following error: Error loading type library/DLL. (0x80029C4A (TYPE_E_CANTLOADLIBRARY)).

So I found via Sysinternals Process Monitor a missing file path for Excel.exe in the Registry for Win32 and changed it to the existing x64 version:

[HKEY_CLASSES_ROOT\TypeLib\{00020813-0000-0000-C000-000000000046}\1.9\0\win32]
@="C:\\Program Files\\Microsoft Office\\Root\\Office16\\EXCEL.EXE"

score 0 · Answer 8 · answered Sep 17 '20 at 06:56

0

In my case I delete regedit in:

HKEY_CLASSES_ROOT\TypeLib\{00020813-0000-0000-C000-000000000046}

delete 1.9

and problem solved.

answered Sep 17 '20 at 06:56

user8124226

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This appears to repeat the accepted answer from 2015 by Jayesh Goyani. – TylerH Oct 21 '22 at 18:38

score 0 · Answer 9 · answered Jun 02 '23 at 12:16

0

Start->Run->Regedit find this path HKEY_CLASSES_ROOT\TypeLib{00020813-0000-0000-C000-000000000046} and remove it and repair your office packet

answered Jun 02 '23 at 12:16

Şöhrət Süleymanov

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Unable to cast COM object of type 'microsoft.Office.Interop.Excel.ApplicationClass' to 'microsoft.Office.Interop.Excel.Application'"

9 Answers9

For Microsoft Office 365 in Windows 10

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