Sheet drop down not populating when selecting an Excel Workbook – TracerPlus

Depending on how Microsoft Office has been installed to your PC/Server, you may find that your Sheet drop-down is not being populated in TracerPlus Connect once you select an Excel Workbook. If you look in the event log, you may see an error like the one below:

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

We recommend trying the below if you are seeing this behavior:

Try a "Repair" of Microsoft Office on this PC.
Try removing all version of Microsoft Office that show in the Add/Remove programs area, then re-install the current version of Office you intend to use.

If the above doesn't work, see the article below from Microsoft with instructions on modifying the registry to remove any leftover components from an older version of office, especially if you have done an upgrade from an old version of office.

https://blogs.msdn.microsoft.com/dau-blog/2012/04/20/how-to-solve-unable-to-cast-com-object-of-type-microsoft-office-interop-excel-applicationclass-to-interface-type-microsoft-office-interop-excel-_application/