How to Fix Corrupted PDF Attachments in Outlook 2016
Question details
User is experiencing an issue where PDF attachments become corrupted intermittently when saved to Drafts or sent.
- Product
- Microsoft Outlook 2016
- Device & OS
- not provided
- Scenario
- Attaching and sending PDF documents via email.
- Observed behavior
- PDF attachments become corrupted before leaving Exchange, either in the Drafts folder or during sending, though subsequent attempts to send the same file sometimes succeed.
Before modifying advanced email settings, verify that your local PDF reader application and Microsoft Office 2016 are fully updated to their latest versions.
Adjust Attachment Workflow and Disable Add-ins
Modifying how you attach files and disabling conflicting add-ins can resolve intermittent file-locking issues that cause corruption.
Corruption occurring before the message leaves Exchange indicates a local file-handling problem. Third-party add-ins, especially antivirus scanners or PDF previewers, can lock the file while Outlook is attempting to process it.
Ensure the PDF is completely saved to your local hard drive (rather than a network or cloud synced folder) before dragging it into an Outlook email draft.
In Outlook 2016, navigate to File > Options > Add-ins. At the bottom, select 'COM Add-ins' from the Manage dropdown and click 'Go'. Temporarily uncheck third-party security or PDF preview add-ins, then click OK.
Try sending the same PDF via Outlook Web Access. If the file sends without corruption in OWA, it confirms the issue is isolated to the desktop client's workflow.
Repair the Office 2016 Installation
Running a repair on Microsoft Office can fix core application files that might be causing attachment encoding errors.
Try WPS Office for Seamless PDF and Document Management
If Outlook 2016 continues to corrupt your files, consider switching to WPS Office. It offers a lightweight, highly compatible productivity suite with a robust built-in PDF editor and safe, seamless document sharing capabilities.
- 1. Download WPS Office: Visit the official WPS website and download the free installer for your operating system.
- 2. Install the suite: Run the installer and complete the quick setup process to access the full suite of tools.
- 3. Manage PDFs securely: Open your PDF documents in WPS Office to edit, compress, or share them securely without worrying about file corruption.
Frequently Asked Questions
Why do my PDF attachments only corrupt sometimes in Outlook?
Intermittent corruption is often caused by third-party antivirus scanners, cloud sync clients, or PDF previewers temporarily locking the file while Outlook is trying to encode it for sending or saving to the Drafts folder.
How can I recover a corrupted PDF sent via Outlook?
Once a file is corrupted during the Outlook sending process, the attachment itself usually cannot be recovered or repaired. You must locate the original, uncorrupted local copy of the PDF and resend it.
Why does resending the same PDF work on the second try?
On the second attempt, background processes that previously locked the file (such as a security scan) may have finished running. This leaves the file unlocked, allowing Outlook to read and attach it cleanly.
Does upgrading from Outlook 2016 fix PDF corruption?
Upgrading to a newer version like Outlook 365 can resolve underlying bugs in the 2016 client's file-handling workflow, though you should first test disabling conflicting COM add-ins before upgrading.
