Published by Letter Opener GmbH

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Why should I report an Issue with Winmail.dat, MSG, MHT Viewer?

  1. AppContacter will directly Email your issue/feedback to an apps's customer service once you report an issue and with lots of issues reported, companies will definitely listen to you.
  2. Pulling issues faced by users like you is a good way to draw attention of Letter Opener GmbH to your problem using the strength of crowds.
  3. Importantly, customers can learn from other customers in case the issue is a common problem that has been solved before.
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About Winmail.dat, MSG, MHT Viewer

1. Open 📎 Winmail. dat, MSG, EML and MHT files easily and securely Letter Opener has always been the perfect app to open Winmail. dat and MSG e-mail files—the format used by Microsoft Outlook and Exchange—and also internet standard EML email files.

2. Your files are never transferred or shared when you use Letter Opener, and your files and content stays protected on your device.

3. And it’s even easier and more secure with Letter Opener for Android.

4. That’s why we never transfer or shared your files.

5. Privacy and security Privacy and security aren’t just something you should hope for—they’re something you should expect.

6. Supported file types: • winmail. dat or AT00001.

7. Everything is done on your trusted device.

8. Your emails stay your business.

Winmail.dat, MSG, MHT Viewer Customer Insights

1. Huge timesavings.OK, it opens .eml and works fine on a Chromebook - but you should at least have the ability to copy the content from the file to put somewhere else... otherwise it has very limited use.Installed it because I was looking for something to open the Winmail.dat I get sent monthly by email (a magazine) as an attachment that consistently fails to open.

2. A great piece of software.This software sucks! Find a different one PLEASE! Why can't you use something that is used in the rest of the US and not just in your small area? Why do I have to download another useless app, just to use for your (and only your stuff because no one else uses it) convenience? It is not user friendly, does not open easily, viewing is very tedious and time consuming d/t me having to scroll all over to see entire invoice.

3. Totally frustratingNever could open any winmail.dat attachment and even when using other winmail opener apps, I had to search for the file after it had been downloaded and try to have it opened with that specific application.

4. When you open an email on an android phone that has an attachment shown as winmail.dat, when you try to open the attachment, the email opens in a different format with a pdf download link at the bottom of the page.

5. With this app, the first time was a charm! I opened up an email with a winmail.dat attachment, downloaded the attachment and BINGO! Everything opened automatically! Very pleased!I receive a lot of forwarded attachments that come as a .dat file.

6. I recommend this app for anyone struggling to open this type of file, typically sent via email from someone using Outlook, etc.Simple and easy to use.

7. I allowed the app access to my photos and "files" but all it goes to is my photos...I'm not needing to "open" those! What the...? I really don't understand files on a phone; was recommended to download a PDF opener, this seemed to fit the bill, but... Nope, doesn't do it.

8. Gmail doesn't display .emls properly, but this does (dont have filename extensions as they come, not sure if thats why, but both recognise it as mail regardless) This is simple and does what it needs, the ads are in a small soundless animated banner at top which is super reasonable Came back cos I forgot I'd reviewed already & I use this a lot for how simple it is, and a bunch of the negative reviews are really, really weird.

9. Just click on the download button and you will be able to open the attachment if you have a pdf reader on your phone.

10. I was searching for software that would successfully open a proprietary winmail.dat file.

11. Allows you to select File Opener or your common app when accessing the file you choose to open.

Steps to Troubleshoot & Fix Winmail.dat, MSG, MHT Viewer Issues

1. Fix Winmail.dat, MSG, MHT Viewer Not Working/Crashes/Errors/Unresponsive & Black/White screen:


  1. Restart Winmail.dat, MSG, MHT Viewer: Restarting the app will resolve most errors.
  2. Update the Winmail.dat, MSG, MHT Viewer App. Here is how:
    1. On Android goto PlayStore » Search for "Winmail.dat, MSG, MHT Viewer" » Open Winmail.dat, MSG, MHT Viewer » click "Update".
    2. On iPhone, goto AppStore » Your profile » Available Updates » Check for Winmail.dat, MSG, MHT Viewer » click "UPDATE".
  3. Clear Winmail.dat, MSG, MHT Viewer app cache: Clearing cached data will force your app to retrieve the latest data directly from Winmail.dat, MSG, MHT Viewer servers.
    1. On Android, goto Settings » Apps » Select "Winmail.dat, MSG, MHT Viewer" » click Storage » click "Clear Cache".
  4. Check Winmail.dat, MSG, MHT Viewer app permissions. If any of these permissions required to use your device's features are disenabled, Winmail.dat, MSG, MHT Viewer might not work.
  5. Uninstall and reinstall Winmail.dat, MSG, MHT Viewer. If nothing else has worked, completely uninstall Winmail.dat, MSG, MHT Viewer then reinstall.
  6. Restart your device. Last, restarting your device can often clear most problems causing Winmail.dat, MSG, MHT Viewer not working


2. Fix Winmail.dat, MSG, MHT Viewer Server issues & Internet Connection


  1. Check network connection: An unstable Internet will make Winmail.dat, MSG, MHT Viewer be unable to connect to it's servers. Ensure your wi-fi is working then restart app.
  2. Disable VPN: VPN can cause connection errors and lead to Winmail.dat, MSG, MHT Viewer not working. Make sure all VPNs are off
  3. Enable background data: When Background data is turned off, Winmail.dat, MSG, MHT Viewer may not be able to connect to the Internet when running in the background.

Reported Issues