Opening P7S files

Did your computer fail to open a P7S file? We explain what P7S files are and recommend software that we know can open or convert your P7S files.

What is a P7S file?

Associated with the Secure/Multipurpose Internet Mail Extension (S/MIME) protocols, a P7S file is embedded with services for cryptographic security standards. These are related to the functions of electronic messaging apps for authenticating messages and optimizing electronic data integrity during transmission. Also known as PKCS #7 signature files, these P7S files are also embedded with cryptographic services that enable digital signatures for the non-repudiation of electronic message origins.

These .p7s files are not meant to be opened. These are used internally by Microsoft Outlook, AppleMail and other email management applications. It's recommended to leave these P7S files alone, in order for these email tools to continue working properly.

Try a universal file viewer

In addition to the products listed above, I would suggest that you try a universal file viewer like Free File Viewer. It can open over 200 different types of files - and very likely yours too! Download Free File Viewer.

By Prof. Jones (The File Expert)

Chief Content Editor and File Expert

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