Hence, it gives rise to the need to compact OST files. If a stable internet connection is not available, you can work on the OST files that increase their sizes immensely. PST (Personal Storage Table) is required for online email transmission, while the OST (Offline Storage Table) is used while working with Outlook in Offline mode. However, the usage and requirement of both these formats are quite different. Microsoft Outlook stores its data in two file formats, i.e., OST and PST.
