Just tap it. BlueMail reads winmail.dat attachments and opens what's inside, so you don't need a converter, a desktop, or a favour from the sender.
What You'll See
- One attachment inside — it opens straight away, exactly as if it had arrived as a normal attachment. A PDF opens in BlueMail's own viewer, an image opens in the gallery.
- Several attachments inside — BlueMail shows a list headed Attachments from Outlook, with each file's name and size. Tap the one you want.
This works the same on Android, iPhone and iPad, and on the desktop apps.
BlueMail also recognizes the file when a mail gateway has renamed it. Besides winmail.dat, names such as win.dat and att00001.dat are handled, as are messages that declare the file as application/ms-tnef without naming it at all.
What the File Actually Is
When someone writes in Outlook using Rich Text format, Outlook packs the message's formatting and every attachment into a single proprietary container called TNEF, and sends that as one file named winmail.dat. The real documents are inside it — a PDF invoice, a Word file, photos — but nothing outside Outlook could traditionally read the container, so the attachments appeared to have vanished.
Nothing is wrong with the message, and nothing was lost in transit. It is a packaging choice made by the sender's mail client.
If BlueMail Can't Open One
You will see one of two messages:
- "This Outlook attachment has no files in it" — the container was read correctly and genuinely holds no attachments. Some Outlook messages send a winmail.dat that carries only formatting. Nothing is missing; there was never a file in it.
- "Couldn't open this Outlook attachment" — the file could not be unpacked, usually because it arrived truncated or damaged.
In both cases the original file is still yours to keep: save it or forward it as normal, and it can be opened on a desktop or passed back to the sender. Asking them to resend is often the quickest fix for a damaged file.
