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
When you install the Spira MS-Office Add-Ins to help import data into SpiraTest, SpiraPlan or SpiraTeam from Excel, Word or MS-Project the installer will check that you have the Microsoft Visual Studio Tools for Office (VSTO) pre-requisite installed. Sometimes if you have this already installed with a newer version it will prevent the install from completing.
If you have installed the MS-Office Add-In for SpiraTest, SpiraPlan or SpiraTeam and the necessary prerequisites (VSTO and the Primary Interop Assemblies if using the MS-Office 2003 Add-In) but it won't display the Add-In in your instance of MS-Excel, MS-Word or MS-Project, follow these instructions to help us troubleshoot.
Since our MS-Office 2007 Add-In for SpiraTeam uses the Microsoft VSTO technology, it's limited to being installed for a single user on a given PC. However if you need to be able to have multiple users access it, there are some registry keys that you can manually add.