The file format and extension of 'CalcbenchExcelXLL64Packed.xll' don't match. The file could be corrupted or unsafe...

Excel is erroneously trying to load the packed version of the Calcbench Excel Add-in, leading to the below error message...

In Excel go to Options->Add-ins-> Manage: Excel Add-ins ->Go.

Unselect Calcbenchexcelxll64Packed.