People are not receiving my emails that have PDF attachments

Question

People are not receiving my emails that have PDF attachments

Director - Sustainable OSHC 5

Whenever I try sending an email to a colleague with a PDF attachment, it is never received on the other end even though it is "sent". It does not appear in their junk or spam folders.

I am able to send them regular emails or attachments of word docs/images but whenever i try attaching a PDF, they do not receieve the email.

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2 answers

Answer 1

Anonymous

Hi @Director - Sustainable OSHC

Thank you for reaching out via the Microsoft Q&A forum regarding this issue.

From your description, emails with Word or image attachments are delivered successfully, but messages with PDF attachments are not received by your colleagues. This usually happens because many email systems apply stricter security checks to PDF files. Security filters are designed to protect users from potential threats, but sometimes they can be overly cautious and block legitimate files like PDFs.

Here are some steps you can try:

Share a OneDrive link: Upload the PDF to OneDrive (or another company-approved cloud service) and send your colleague the link instead of attaching it directly.
Compress the PDF into a .zip file: Many systems allow zipped attachments even when PDFs are blocked.
Switch your email format to Plain Text: If you are currently composing in HTML or Rich Text, try switching to Plain Text. Instructions are available here: Change the message format to HTML, Rich Text Format, or plain text in Outlook

For a long-term solution, the best step is to contact your IT team. They can review system logs to see exactly why the emails with PDFs are being blocked and help ensure this does not happen again.

I hope this helps you get your email sent. Please let us know if you need further guidance.

If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".

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Director - Sustainable OSHC 5 Reputation points

2025-09-24T22:13:56.2633333+00:00

Hi there,

I've tried your 3 suggestions above but none of them seem to work. It only happens now with specific PDF's - so do you think it is due to a security filter? Is there any way to remove the security filter?
Anonymous

2025-09-25T05:12:46.2+00:00
Hi @Director - Sustainable OSHC

Thanks for your update. Since this issue only happens with certain PDFs, it is likely caused by security filters on your company’s email system. These filters are in place to protect users from potentially harmful files, and unfortunately, end users cannot bypass them directly.

As a Microsoft Community moderator, I don’t have control over these filters. Your IT team is the best point of contact to review the email logs and adjust security policies if needed.

I understand that the workarounds I suggested earlier (sharing via OneDrive/SharePoint or compressing into a .zip file) may not be feasible in your situation. In this case, the next best step is to involve your IT team directly. You can share the following Microsoft references with them for guidance:

Blocked attachments in Outlook

Outlook blocked access to the following potentially unsafe attachments

Common attachment blocking scenarios for Exchange Online

Troubleshoot attachment problems in Outlook for Windows - Microsoft Support

Thanks for your understanding, and I hope this helps your IT team address the issue.
Anonymous

2025-09-29T06:44:18.0966667+00:00

Hi @Director - Sustainable OSHC

Just following up to see if your IT team was able to review the logs and address the PDF blocking issue.

Please let us know if you need any additional guidance or references, we’re happy to help!

Answer 2

Mundy, Robert 0

I'm having same issues. In my case It's only emails where I attach PDF files created from Windows "print to PDF" that are affected. If I install a 3rd party PDF printer I'm able to send the emails and the party receives the email. If I attach a PDF file created with the built in PDF printer the email still shows in my sent folder but the recipient receives no email at all.

Hornblower409 16,350 Reputation points

2026-08-13T14:28:43.81+00:00

@Mundy, Robert said

In my case It's only emails where I attach PDF files created from Windows "print to PDF"

You will not get any help for your issue by adding to an old post about a different problem. I would suggest that you start a new thread using the "Ask a question" button at the top of this page to create a new Question and include the details for *your specific problem.*This provides much higher visibility to your issue than adding on to an existing post, which is only seen by people who are already following this question.