Winmail.dat, MSG, MHT Viewer

Letter Opener GmbH

About this app

Open 📎 Winmail.dat, MSG, EML and MHT files easily and securely

Letter Opener opens winmail.dat and MSG e-mail files as well as EML email files, right on your Android device. It also opens MHT web archives, the format browsers use for saved web pages.

Winmail.dat Viewer — what is a winmail.dat file?

Someone sent you a winmail.dat or ATT00001.dat attachment and it won’t open? That happens when Microsoft Outlook or Exchange packs the message and its attachments into a single winmail.dat file. The winmail.dat viewer unpacks it instantly, so you can read the message and open or save every attachment inside.

MSG Viewer — what is an MSG file?

MSG files are email messages saved from Microsoft Outlook on Windows. The MSG viewer shows you the full message on your phone — text, formatting, and attachments included — and opens Outlook’s OFT template files too.

EML Viewer — what is an EML file?

EML files are saved email messages, used by apps like Apple Mail, Thunderbird, and Gmail — yet most Android phones have nothing to open an EML file with. The EML viewer displays the complete message, attachments and all, and opens Apple Mail’s EMLX files too.

MHT Viewer — what is an MHT file?

An MHT (or MHTML) file is a complete web page saved as a single file, created by browsers like Chrome, Edge and Internet Explorer. The MHT viewer displays the saved page just like the original.

Your files stay private

Nothing uploads to the cloud. Nothing leaves your phone. Letter Opener processes everything locally—because your emails are nobody else’s business.

Supported file types:

• Outlook: winmail.dat, ATT00001.dat, .MSG, .OFT
• E-Mail files: .EML, .EMLX
• Web archive files: .MHT, .MHTM, .MHTML, .WEBARCHIVE
• Documents: .RTF
• Images: .TIFF, .TIF, .HEIC, .HEIF, .JP2, .J2K, .JPF, .JXL, .WMF, .EMF

Made with a special 😤 for winmail.dat files.

Ratings and reviews

Has been perfect until now, but won't open files after recent update (error messages indicating 'unrecognised format'). I tried restarting the phone, but it made no difference. UPDATE: I installed a different app which DID then open files correctly, however, I was now getting a prompt asking me choose which app to use. Out of interest I had a go with Letter Opener again - what do you know, it now worked again! I deleted the new programme and Letter Opener continues to work...

I have used it twice to open email attachments. The first email it failed to open the attachment, and the second it it opened a url link.

Can't understand why Letter Opener is being killed, but I don't understand media technology. It helps me easily open winmail in my emails. Happy with this service.

What’s new

Initial Release 🎉