Since Office 2013 no longer receives security updates, having a reliable backup of the installation media is only half the battle. Maintaining the is the more critical "media" element today. This key is often embedded in the Microsoft Account or found on the original Certificate of Authenticity (COA) for retail copies.
Pro tip: The specific ISO you need depends on your product key (Retail, Volume, or Home & Business). Downloading the wrong version (e.g., VL vs. Retail) will reject your valid key. office 2013 backup media
If you possess an original retail DVD but want to protect it from degradation: Microsoft Learn Since Office 2013 no longer receives security updates,
Your backup download will likely end in .img . This is a disc image file. Pro tip: The specific ISO you need depends
Office 2013 Backup Media: Safeguarding Your Installation Files
Store the installer and a digital copy of the product key in multiple locations (e.g., an external hard drive and an offline vault).