Why is the PST file size larger than the original OST file when saving with Aspose?"
No need to code
Hello @Anjali12,
The difference in file size between OST and PST is expected and results from several factors:
OST and PST files have a bit different internal architecture. OST is optimized for local caching by Outlook, while PST is designed for broader compatibility and long-term storage.
Different creators (Outlook vs. Aspose.Email) handle internal storage and free space differently, which affects the overall file size.
OST files use compression not always replicated in PST.
Due to the complex and layered nature of the PST/OST file formats, you will never get identical sizes between the two. It’s simply not a one-to-one conversion at the byte level, and that’s normal.