PDF attachments from outlook open in reader instead of full acrobat

Question

Hello all,

I think the subject describes the issue. I have set Acrobat as the default app, and I have tried managing the Outlook add-in, but PDF attachments still open in Reader rather than full Acrobat when I open a PDF from an attachment. If I save the attachment elsewhere, then it will open in the full version. Any ideas on how I can open a PDF directly to the full version when opening from an attachment in Outlook?

davidm19816265 · Accepted Answer

What happens if you disable Sure Click?Are you in a corporate environment?What happens if you disable the Attachment Preview in Outlook? It looks like Sure Click opens the PDF in a quarantined version of Acrobat Reader to guard against malware and phishing links, etc. I'm not going to mess with it. Now that I know what is going on I can bite the bullet and save the PDF files I need locally and then open them in the full version. Thank you for the input.

Tariq Ahmad · Answer

Hi @davidm19816265,

That does sound frustrating — thank you for detailing what you’ve already tried. What you’re running into is a known behavior with Outlook: when you open a PDF directly from an attachment, it first saves a temporary copy into Outlook’s cache folder. Windows then uses whichever PDF handler is associated with certain registry entries for “Outlook temp files,” which can differ from your system-wide default. That’s why saving the file elsewhere works correctly, but opening directly from Outlook defaults to Reader.

A few things you can try:

Check Windows Default Apps
- Confirm under Settings > Apps > Default apps that Adobe Acrobat (not Reader) is set as the default for .pdf.
- Sometimes, uninstalling Reader (if not needed) resolves this completely, since Windows and Outlook will only see Acrobat as the handler.
Repair Office + Acrobat
- Run a Quick Repair on Outlook/Office.
- In Acrobat, go to Help > Repair Installation.
Outlook Trust Center Settings
- Outlook has its own attachment handling logic. Go to File > Options > Trust Center > Trust Center Settings > Attachment Handling. Check whether any PDF previewer or Reader reference is active there. If so, disable/unregister it.
Registry-level fix (advanced)
- In some cases, the “PreviewHandler” or AcroExch.Document.DC vs. AcroExch.Document.Reader association needs adjusting in the registry. This is more advanced, so if the issue persists, Adobe/IT admins may need to align those keys so that attachments also honor the Acrobat app.

As a quick test, if you temporarily uninstall Reader, Outlook should begin opening attachments in Acrobat, confirming that this is indeed a handler conflict.

Let us know how this goes.

Best regards,
Tariq | Adobe Community Team

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