Articles Tagged 'ms-project'

Articles
Resolving 'Unable to cast COM object' errors when using MS-Office Add-Ins

Sometimes when using our MS-Office Add-Ins (for Excel, Word and Project) on a new computer you will see an error message of the type:

Unable to cast COM object of type 'System.__ComObject' to interface type 'Microsoft.Office.Tools.Excel.Worksheet'. This operation failed because the QueryInterface call on the COM component for the interface with IID ...

This article explains the cause of these types of error and provides some common solutions