PDF Opening Issues

Fix Unable to Open PDF Attachments in Outlook on iPhone

Camila Milosovich Oct 19, 2026 868 views

Question details

The user is unable to open or view PDF file attachments within the Outlook 365 app on their iPhone.

How to Fix: Unable to Open PDF Attachments from Outlook on iPhone

Product: Outlook 365 iOS
Device & OS: iOS (iPhone)
Scenario: Attempting to open and view a PDF document that was attached to an email received in the Outlook app.
Observed behavior: The PDF attachment fails to load properly when tapped inside the Outlook email client.

Before you start

Check the App Store to ensure both your Microsoft Outlook app and your preferred PDF reader app are updated to their latest versions.

Solution 1Recommended

Use the iOS Share Sheet to Open in a Dedicated PDF Reader

Bypass Outlook's built-in previewer by sending the file to an external PDF reading app like Adobe Acrobat Reader or WPS Office.

Sometimes the built-in document previewer in iOS or the Outlook app glitches when handling certain PDF encodings. By utilizing the 'Share' or 'Open In' functionality, you can route the document to an application specifically designed to read PDFs.

Open the email in Outlook

Navigate to your inbox in the Outlook app and open the email containing the PDF attachment.

Tap the attachment

Tap on the PDF attachment to trigger the download and open the preview screen.

Access the Share menu

Tap the 'Share' icon (a square with an upward-pointing arrow) typically located in the top right corner of the screen.

Select your PDF app

Scroll through the horizontal list of apps and tap on your preferred PDF viewer (e.g., Acrobat) to open the file.

Use the iOS Share Sheet to Open in a Dedicated PDF Reader

App Not Showing?: If you don't see your PDF app in the list, scroll to the far right, tap 'More', and add it to your favorites.

Solution 2

Verify Adobe Acrobat Account and Subscription

Ensure that your PDF reader is properly authenticated, especially if you are trying to edit or use premium features on the PDF attachment.

Reliable PDF Viewer for iPhone

Open and View PDF Attachments Effortlessly with WPS Office

WPS Office for iOS includes a powerful, built-in PDF reader that allows you to easily open, read, and annotate PDF attachments straight from your email apps without relying on basic previewers.

1. Install WPS Office: Download and install WPS Office for free from the Apple App Store.
2. Open the Outlook attachment: In your Outlook app, tap the PDF attachment to load the preview.
3. Tap the Share icon: Select the 'Share' or 'Open In' icon at the top of the screen.
4. Choose WPS Office: Select 'WPS Office' from the list of available apps in the iOS share sheet.
5. View and edit: The PDF will instantly open in WPS Office, ready for you to read, highlight, or sign.

Seamlessly opens PDF files from Outlook, Apple Mail, and other email clientsFully compatible with standard Microsoft Office and Adobe PDF formatsIncludes advanced tools to annotate, sign, and share PDFs directly from your iPhone

microsoft office alternative - wps office

Frequently Asked Questions

Why does Outlook on my iPhone fail to open PDF files?

This can happen due to a corrupted app cache, an outdated version of the Outlook app, or temporary glitches in the built-in iOS PDF previewer. Sending the file to a dedicated PDF reader usually bypasses this issue.

How can I set a default PDF reader on my iPhone?

Unlike desktop computers, iOS does not allow you to set a system-wide default app for opening specific file types like PDFs. However, you can consistently use the 'Share' menu to open PDFs in your preferred application.

Is it safe to open PDF attachments on an iPhone?

Yes, iOS provides a secure environment (sandboxing) that prevents malicious scripts from easily executing. However, you should still only open attachments from trusted senders to avoid phishing attempts.

PDF Troubleshooting