Microsoft Office 2013 Portable Guide

A of Office 2013, by contrast, is a modified or repackaged version of the software that is designed to run entirely from a removable storage device (like a USB 3.0 flash drive) or a cloud-synced folder. In theory, you should be able to plug the drive into any Windows computer, launch Word or Excel from the drive, edit your documents, save them back to the drive, and then remove the drive without leaving any personal data, cache files, or registry changes on the host machine.

This is the most critical section.

A of Office 2013, by contrast, is a modified or repackaged version of the software that is designed to run entirely from a removable storage device (like a USB 3.0 flash drive) or a cloud-synced folder. In theory, you should be able to plug the drive into any Windows computer, launch Word or Excel from the drive, edit your documents, save them back to the drive, and then remove the drive without leaving any personal data, cache files, or registry changes on the host machine.

This is the most critical section.