How to set AUTO rotation of ALL PDFs to always open in landscape orientation?

Hello @barry_2556

I hope you are doing well, and thanks for reaching out.

There is no global setting in Adobe Acrobat Reader that forces all PDFs to open in landscape orientation by default. Acrobat respects the original orientation of the PDF as defined during scanning or creation. This is why your documents—scanned in portrait—always open that way.

Even though you can rotate the view manually (via View > Rotate ViewThis change is temporary and resets when the file is reopened

Workarounds You Can Try: 

Use Auto Portrait/Landscape in Print Settings: If you want to print in landscape, regardless of the scan orientation, open a PDF and go to Menu > Print. In the print dialog, select “Auto portrait/landscape” under Page Sizing & Handling. Save this as a custom preset in your printer settings
Note: Acrobat uses the printer driver’s default orientation. So if your printer is set to portrait, Acrobat will follow that unless overridden.

Batch Rotate PDFs Before Use: If you receive many PDFs in portrait but want them in landscape, use Organize Pages > Rotate in Acrobat Pro (not Reader) to rotate pages in bulk.

Automate with Acrobat Pro Actions (if available). If you have access to Acrobat Pro, create an Action Wizard to rotate all pages to landscape. Apply this action to folders of scanned PDFs.

I hope this helps.

Thanks,

Anand Sri.