In Office, to open any files that contain Macros, you will need to make sure that your Excel settings are not too strict, as the Rental Workbook will not open correctly otherwise.

Rather than Enabling All Content (Not recommended), we suggest that you add the folder where you store your Rental Workbook to a Trusted Location – for example My Documents > Rental Workbook.

Microsoft regularly makes updates to its programs, and Office is no exception, however this link will take you to Trusted Locations – Microsoft