Sometimes, you create new application pool and cann't solve it via DCOMCNFG. Then there is another method to do:

Set the Identity (Model Name) of application pool to LocalSystem.

I don't know the root cause, but it solve my problem one time.

Too late to respond. But, if this helps someone who is still facing the issue. I got this fixed by:

→ Set site on dedicated pool instead of shared one.

→ Enable 32 bit application support.

→ Set identity of the application pool to LocalSystem.

1. give the read / write permission to the IIS user or group users

2. Start -> run -> inetmgr

   enable the ASP.NET authentication for your default website

3. For 64-bit (x64), create this folder: C:\Windows\SysWOW64\config\systemprofile\Desktop

For 32-bit (x86), create this folder: C:\Windows\System32\config\systemprofile\Desktop

The windows service, if running under the systemprofile, needs the Desktop folder. This folder was automatically created on XP and older Windows Server versions, but not for Vista and Windows 2008 Server.

solution that worked for me is to change user under which Application Pool is started (ApplicationPoolIdentity obviously has not enough rights to access COM object).

Good luck!

try to do the following:

1. Make sure Office interop assemblies are installed.
2. Check the version of the assemblies on development and production.
3. Create Desktop folder under systemprofile.
4. set the DCOM security explicitly for the service user.

you can find more details here

Personally, I ran these exact steps:

* Install Interop Assemblies: you can install from Microsoft's website https://www.microsoft.com/en-us/download/details.aspx?id=3508&tduid=(09cd06700e5e2553aa540650ec905f71)(256380)(2459594)(TnL5HPStwNw-yuTjfb1FeDiXvvZxhh.R.Q)()

* Check assemblies version: check the version of the assemblies on development and production machines. The assemblies will be in the GAC, in widows 7 this folder is %windir%\assembly.

* Create a Desktop folder: the service uses the desktop folder under systemprofile so you will need to create this folder if not there, here is the location of the folder: For 64 bit applications : C:\Windows\SysWOW64\config\systemprofile\Desktop For 32 bit applications : C:\Windows\System32\config\systemprofile\Desktop

* Add DCOM user permissions:
---start the run window and type 'dcomcnfg'.
---Expand Component Services –> Computers –> My Computer –> DCOM Config.
---Look for Microsoft Excel Application. Right click on it and select properties, then select the Security tab.
---Select the Customize radio button under 'Launch and Activation Permissions' and 'Access Permission' and click the Edit button for both to add users as follows.
---------Click the Add button and users 'IIS_IUSRS' and 'NETWORK SERVICE' and give them full privileges.
---Go to the Identity tab and select "The interactive user" option.
---Click Apply and OK.

I just created a simple application

What is the target processor of the application? I am guessing it is x86 - so either set it to x64 or anycpu.

I think the issue you are having is due to a 64bit process trying to access a 32bit dll.

Also, if you can't change the target processor you could try to enable 32-bit Applications from the Application Pools settings in IIS.

Do you have Excel installed on the server? The interop interfaces you're using are used to automate Excel which requires that the Excel application is installed there. Each page request cycle will potentially launch a separate instance of excel.exe. I would strongly advise against doing this as part of a web application.

Why do you want to do this? If you are wanting to generate Excel documents, there are much better ways to do this, including OpenXML as mentioned elsewhere on this thread. Please do not run Excel on the server!

Link to OpenXML SDK download: http://www.microsoft.com/en-us/download/details.aspx?id=5124

This looks like a permission problem. I suggest running processMonitor to determine what permissions are needed.

use NPOI to read and write excel..it's free and open source

for exapmle

using NPOI.HSSF.UserModel;
using NPOI.SS.UserModel;

//.....

private void button1_Click(object sender, EventArgs e)
{
    HSSFWorkbook hssfwb;
    using (FileStream file = new FileStream(@"c:\test.xls", FileMode.Open, FileAccess.Read))
    {
        hssfwb= new HSSFWorkbook(file);
    }

    ISheet sheet = hssfwb.GetSheet("Arkusz1");
    for (int row = 0; row <= sheet.LastRowNum; row++)
    {
        if (sheet.GetRow(row) != null) //null is when the row only contains empty cells 
        {
            MessageBox.Show(string.Format("Row {0} = {1}", row, sheet.GetRow(row).GetCell(0).StringCellValue));
        }
    }
}  

see this Stackoverflow question

Use this

create a user in admin group

add this user details in web config like below

<system.web>
   <identity impersonate="true"
    userName="User Name"
    password="Password" />
    `enter code here`</system.web>

restart the IIS and check again

-tony-

Came across this issue two days back, spent whole complete two days, So I found that I need to give the access to IUSR user group at DCOMCNFG --> My Computer Properties --> Com Security --> Launch and Activation Permissions --> Edit defaults and give all rights to IUSR.

hope it will help someone....

If you are trying to configure this on 64bit, you have to do your DCOMconfig configuration (see other answers above) in:

C:\WINDOWS\SysWOW64>mmc comexp.msc /32

according to Setting Process-Wide Security Using DCOMCNFG.

After this, I was able to configure this for IIS_IUSRS without administrator privileges.