I've been experiencing a frustrating issue in Outlook (Classic) for the past 3-4 weeks where PDF attachments take an eternity to load—about 5-10 minutes of endless spinning. This issue isn't affecting all users; it's showing up for around 25% of our team. I've ruled out a recent update as the entire setup is current, and the problem is selective, only impacting Classic Outlook, not the New version. I've already gone through several fixes:
1. Cleared the %temp% folder.
2. Performed a repair on Office, even uninstalled it completely and reinstalled after cleaning out the registry.
3. Ran Outlook in safe mode, checked attachment preview settings, and created new mail profiles.
4. I also did some network resets due to changes by Microsoft.
Our machines are fairly decent—11th and 12th gen i5 processors with 16GB or 32GB RAM, all using NVMe drives. We use MDO/DFE with consistent policies across all users. Has anyone else encountered similar issues, or have suggestions to troubleshoot this?
5 Answers
In Classic Outlook, try disabling the Acrobat PDFMaker Office COM add-in and the Adobe Document Cloud add-in for Outlook. I've found that many PDF issues with Outlook get resolved this way, especially the Cloud one!
Do you have Acrobat installed on your users' systems? Switching to 'enable new Acrobat' has helped some folks avoid similar issues, just a thought!
A few users do have Acrobat Pro, while others use PDF-Xchange or just Edge/Word. I didn’t find a solid link among them, though.
Does the issue happen immediately when the email arrives, or does it require user action, like clicking the email or opening the attachment? I've seen some Outlook versions hang like that for a few minutes when opening any PDF. Restarting usually provides a temporary fix.
Have you tried using CoPilot to analyze the PDFs? It can check for problems like JavaScript or external links that might be causing these slowdowns. Might be worth a shot!
I'm not sure if that helps if multiple PDFs are affected. You could test by sending a blank PDF to see what happens.
Good idea, but my experience is that it happens with many different PDFs, both internal and external, so I'm doubtful.
I tried safe mode, which disabled those add-ins, but the problem persisted. Still spinning, unfortunately.