Attachment Issues

How to Troubleshoot Outlook Formatting and Attachment Problems

Partner Editor Oct 12, 2026 868 views

Question details

The user needs to resolve recurring issues with Outlook failing to retain font settings, sending incomplete emails, and being unable to open PDF attachments.

How to Troubleshoot Outlook Formatting and Attachment Problems

Product: Microsoft Outlook
Device & OS: not provided
Scenario: Sending emails with specific formatting and opening PDF document attachments.
Observed behavior: Outlook fails to retain text formatting, sends out incomplete messages, or repeatedly fails to open attached PDF files.

Before you start

Verify your internet connection stability and confirm whether you are using the Outlook desktop app, the web version, or the mobile application before proceeding with troubleshooting.

Solution 1Recommended

Run Outlook in Safe Mode and Disable Add-ins

Third-party add-ins can often interfere with email formatting and prevent attachments from opening correctly.

Running Outlook in Safe Mode launches the application without custom toolbar settings or COM add-ins, helping you determine if a third-party extension is causing the attachment and formatting issues.

Launch Safe Mode

Press the Windows key + R to open the Run dialog box. Type 'outlook.exe /safe' (without quotes) and press Enter.

Test Email and Attachments

Try sending a formatted email or opening a PDF attachment. If it works, an add-in is the likely culprit.

Disable Suspicious Add-ins

Go to File > Options > Add-ins. At the bottom of the window, ensure 'COM Add-ins' is selected in the Manage drop-down list and click 'Go'. Uncheck the boxes next to your active add-ins and restart Outlook normally to see if the issue is resolved.

Run Outlook in Safe Mode and Disable Add-ins

Identifying the Problematic Add-in: If disabling all add-ins fixes the issue, re-enable them one by one, restarting Outlook each time, to isolate which specific add-in is causing the failure.

Solution 2

Update Outlook and Windows

Outdated software can contain known bugs that affect message rendering and attachment handling.

Solution 3

Verify Attachment Size Limits and Repair Data Files

Corrupted Outlook data files or exceeding server attachment limits can result in incomplete messages and failed PDF deliveries.

Free Microsoft Office alternative

Handle Office Files and PDF Attachments Easily with WPS Office

If Outlook continues to struggle with Microsoft Office files or opening PDF attachments, try using WPS Office as your primary document handler. It offers a lightweight, robust suite for Word, Excel, PowerPoint, and PDF files, making it a perfect, hassle-free alternative to Microsoft Office.

1. Download and Install: Download WPS Office for your Windows, Mac, or mobile device and follow the simple installation prompts.
2. Save the Attachment: If Outlook fails to open a file directly, right-click the attachment in your email and select 'Save As' to download it to your local storage.
3. Open with WPS Office: Locate the saved document or PDF and open it seamlessly using WPS Office's built-in reader.

Fully compatible with Microsoft Office formats like .docx, .xlsx, and .pptx.Features a built-in, powerful PDF reader and editor to easily open and manage email attachments.Lightweight architecture ensures fast loading times without consuming excessive system resources.Free to use with a familiar, user-friendly interface that requires zero learning curve.

microsoft office alternative - wps office

Frequently Asked Questions

Why does Outlook change my font formatting when sending an email?

This often happens if your email message format is set to 'Plain Text' instead of 'HTML'. To fix this, go to the 'Format Text' tab in your new email window and click on 'HTML' before formatting and sending your message.

How do I bypass the 20 MB attachment size limit in Outlook?

If your PDF or document exceeds the default allowable limit, you cannot attach it directly. Instead, upload the file to a cloud storage service like OneDrive, Google Drive, or Dropbox, and insert the sharing link into your email body.

Why can't I open PDF attachments directly from Outlook?

This usually occurs if your default PDF reader is missing, outdated, or conflicting with Outlook's preview handler. You can resolve this by saving the PDF to your desktop first, or by reinstalling a dedicated PDF application like WPS Office to reset your system's default file associations.

Outlook & Email Problems