If PDF files won't open on your Android phone, the problem is almost always the default PDF viewer app — it may be missing, out of date, or set to an app that can't handle the file. The fix takes a couple of minutes, and it works the same way on any Android device, including Samsung phones.
The easiest fix: make BlueMail your PDF viewer
BlueMail is a free PDF viewer for Android — and it opens any PDF you tap, wherever it came from. You don't have to be in an email to use it:
- Tap a PDF anywhere and it opens. From Downloads, your file manager, a chat, a browser download or a link — BlueMail appears in the "Open with" list and can be set as your Android default, so PDFs just open.
- Email attachments open instantly. Tap a PDF in a message and it opens right there — no "Open with" prompt, no bouncing between apps, no waiting for a separate viewer to load.
- One app instead of two. If your invoices, tickets, statements and contracts arrive by email anyway, you get both in a single app rather than installing a dedicated reader alongside it.
Download BlueMail free from Google Play →
Then follow the steps below to make it your default — after that, every PDF you tap opens straight away.
Step 1: Clear Default App Settings
If another app is already set as your default PDF viewer, clear it first:
- Open the Settings on your Android device.
- Navigate to Apps or Applications (this may vary depending on your device).
- Locate and select the PDF viewer app you're currently using.
- Tap on Open by default or Set as default.
- Choose Clear defaults to remove the app as the default PDF viewer.
This is also how you stop an app opening your PDFs if you'd rather it didn't — clearing its defaults hands the choice back to you the next time you tap a file.
Step 2: Select Your New Default PDF Viewer
- Open any PDF file on your device.
- When prompted, select BlueMail (or another viewer) from the list of available apps.
- Tap Always to set it as your new default PDF viewer.
That's it — PDFs will now open in your chosen app every time. If BlueMail doesn't appear in the list, update it to the latest version from the Google Play Store.
Updating your PDF reader
If PDFs used to open and suddenly stopped, the viewer itself is often just out of date. Open the Google Play Store, tap your profile icon, choose Manage apps & device, then Updates available, and update your PDF app if it's listed. An app that fails to open files it handled last week is usually a version behind, not broken — and the same applies to BlueMail if attachments stop opening.
Other PDF viewer apps
If you'd rather use a dedicated PDF app alongside your email, these are also available on the Play Store:
- Adobe Acrobat Reader
- Files by Google, which includes a built-in PDF viewer
- Google Drive, which opens PDFs without any extra app
Still not opening?
If PDFs still won't open after changing the default app, the file itself may be the problem rather than the viewer:
- The download may be incomplete. Try downloading or saving the file again.
- The PDF may be password-protected. Some viewers won't prompt for the password and simply fail to open the file.
- The file may not be a PDF at all. Occasionally a file has a
.pdfname but different contents, which no PDF viewer can display.
