pdf received via email (Outlook) won't open on Mac

I will my voice to the chorus: suddenly unable to open pdfs and Adobe Acrobat will not launch.  It just bounces a bit, and dies in the tool bar.

Hi ERINMCLEAN,

Thank you for reaching out, and sorry to hear about the trouble. Since this started today and you're seeing the same behavior with PDF attachments from multiple senders, let's try a few checks to narrow down where the issue is occurring.

1. Check whether PDFs already stored on your Mac open normally: 
   Open a PDF directly from Finder using Adobe Acrobat/Acrobat Reader. If locally stored PDFs open successfully, this would suggest focusing troubleshooting on the email attachment/download workflow rather than the PDF application itself.

2. Try saving/downloading the attachment first:
   If Outlook allows it, save the attachment to a local folder such as Downloads and then open it from Finder. Adobe also recommends downloading a problematic PDF locally and opening the downloaded copy directly in Acrobat/Reader when troubleshooting PDF-opening problems. 

3. Test the attachment outside Outlook.
   As an isolation test, try accessing the same message/attachment through Outlook on the web or another available mail client/browser. If the attachment works there but not in the Outlook desktop application, that helps narrow the issue to the Outlook-side attachment workflow rather than Acrobat.

4. Update Acrobat/Reader and restart the Mac.
   In Acrobat/Reader, choose Help > Check for Updates and install any available updates. Adobe specifically recommends keeping Acrobat/Reader current when PDFs fail to open. 

5. Verify the default PDF application.
   In Finder, select a PDF and choose File > Get Info > Open with, select Adobe Acrobat or Acrobat Reader, and use Change All if you want PDFs to open with it by default. These are Adobe's documented macOS steps. 

6. Rule out a damaged attachment.
   If you manage to save one of the affected files but it fails in both Acrobat and Apple Preview, ask the sender to resend or regenerate the PDF. Adobe notes that a corrupt/damaged PDF cannot be directly repaired and may need to be recreated from its original source. 

Please also refer to the suggestion in the following help document: Can't open PDF.

For further assistance, please let us know if you receive any error messages when attempting to open the PDFs from Outlook. Additionally, share the version details for Outlook, Acrobat, and macOS. A short video demonstrating the issue would also be very helpful.

Let us know how it goes.

Thanks,

Meenakshi