Outlook Add-in Error

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Outlook Add-in Error
Brett Lim

Posts: 12
Joined: 2018-04-11

One user is experiencing an error using an Outlook Add-in as below:
Unable to cast COM object to type 'System.__ComObject' to interface type 'AddinExpress.MSO.IRibbonUI'. This operation failed because the QueryInterface call on the COM component for the interface with IID '{000C03A7-0000-0000-C000-000000000046}' failed due to the following error: Error loading type library/DLL. {Exception from HRESULT: 0x80029C4A (TYPE_E_CANTLOADLIBRARY)}

The user is on Windows 10 (x64) with Office 365 (x86) and Add-in Express 8.9.4453.

Are you aware of this error?

Posted 15 May, 2018 19:32:21 Top
Andrei Smolin

Add-in Express team

Posts: 15108
Joined: 2006-05-11
Hello Brett,

Is it possible that you access Ribbon components from a background thread? You should only access them from the main thread. This is because they use the Core Office object model and you should only access Office COM objects from the main thread.

Regards from Belarus (GMT+3),

Andrei Smolin
Add-in Express Team Leader
Posted 16 May, 2018 01:42:33 Top