You choose a file
Use the picker or drop a `.dat` attachment onto the opener. Files are checked for type and size before processing.
How it works
What happens to your file.
Winmail.dat Opener is a small browser utility for one specific email problem: getting the real attachments back out of a TNEF container, whether it is named winmail.dat or ATT0001.dat.
Your browser reads it
The file is read with browser APIs and decoded in memory using a TNEF parser. There is no upload request for the file bytes.
You save the results
Recovered attachments become local download links. You can save one file or create a ZIP directly on your device.
Privacy note
Your file does not need to leave your device.
Like any browser tool, this page still needs to load its code and assets. The selected file itself is processed locally; it is not sent to Winmail.dat Opener or another service.