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Interface not registered (Exception from HRESULT: 0x80040155) – Microsoft Office/Outlook Error'

If you recently uninstalled Outlook 2013 or Outlook 2016 or have a problem with your Outlook installation then you may encounter the following error messages:

Unable to cast COM object of type ‘Microsoft.Office.Interop.Outlook.ApplicationClass’ to interface type ‘Microsoft.Office.Interop.Outlook._Application’.

This operation failed because the QueryInterface call on the COM component for the interface with IID ‘{00063001-0000-0000-C000-000000000046}’ failed due to the following error: Interface not registered (Exception from HRESULT: 0x80040155).

The root issue is that their is a problem with the Outlook installation Common Object Model (COM) interface where the version reference for the TypeLib entry set by the Outlook installation is pointing to a incorrect value/version or that version does not point to a correct location. The following steps should help correct the most common cause of this issue issue. If you continue to have issues then you may need to reinstall Microsoft Outlook. Repairing the Outlook installation does not fix this issue so a reinstall is suggested.

Even after running through reinstallation or repairing of Outlook/Office it didn’t fix for us, so after researching through google we came across solution listed on GitHub Wiki by Paul Woolcock

For more details on the fix please visit


This can be a particularly nasty problem. Follow through the steps:

Register Ole32.dll

Make sure part of Microsoft Office (the Ole32.dll file that is located in the %windir%/System32folder) is registered correctly in the Windows registry:

1. Click Start, and then type Command Prompt, in appeared list, right-click Command Prompt and select Run as Administrator
2. In Command Prompt window type the following command and press Enter
For 32 bit Windows: regsvr32.exe %windir%/System32/Ole32.dll
For 64 bit Windows: %systemroot%/SysWoW64/regsvr32.exe %windir%/SysWoW64/Ole32.dll
3. In the RegSvr32 dialog box, click OK.
Then follow the 3 steps through below from fix the interface to ensure MSOUTL.LIB is registered (the final step usually being the most important).

Registry Fixes:

Step through the following sections.
It is always wise to backup your Windows registry before making any manual changes.

Outlook Version Numbers
Use this table as a reference as guided in the following sections.

Outlook Version
Outlook 2003 - 9.2
Outlook 2007 - 9.3
Outlook 2010 - 9.4
Outlook 2013 - 9.5
Outlook 2016 - 9.6

1. Fix the Interface

1. Access the Windows Registry Editor via Start > Run > Type Cmd and Enter > Type RegEdt32 and Enter.

2. Navigate to each of the keys that exist (depends on if using the 32 or 64 bit version of Outlook/Windows):

3. Find a (Default) entry with the value {00062FFF-0000-0000-C000-000000000046}

4. Compare and correct the Version value against the Outlook version numbers table.

2. Fix the TypeLib

1. Navigate to HKEY_CLASSES_ROOT/TypeLib/{00062FFF-0000-0000-C000-000000000046}

2. Delete the version keys (e.g. 9.5) for any version of Outlook that is not installed on your system, based on the version table provided.
For example, if you are not using Outlook 2013 then remove the 9.5 entry. If you are not using Outlook 2010 then remove the the 9.4 entry.
DO NOT DELETE the entry for the version that was specified in the last step of the previous fix the interface section.

3. Ensure MSOUTL.LIB is Registered

1. In the previous fix the typelib section, make sure that the registry key value ending with MSOUTL.OLB is pointing to a valid file location. The key location should be something like HKEY_CLASSES_ROOT/TypeLib/{00062FFF-0000-0000-C000-000000000046}/9.6/0/Win64

2. We now need to make sure that file is properly registered.
1. Download regtlibv12.exe to your computer
2. Go the Windows Start Menu and type cmd.
3. In the search results, right-click cmd.exe and select Run as Administrator...
4. Change directory to where you downloaded regtlibv12.exe, eg: cd %USERPROFILE%/Downloads
5. Execute the following command, where <msoutl.olb file> is the value taken from step #3:
regtlibv12.exe '<msoutl.olb file>'.
For example:
regtlibv12.exe 'C:/Program Files/Microsoft Office/root/Office16/MSOUTL.OLB'

3. Run Outlook.

Last updated, 12 September 2019, 13:59

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