There appears to be an unresolved bug (as of writing this article) for users using Windows 10 and the free Adobe Reader in which only one PDF can be opened at a time.
Users can open the first PDF normally. However, once the Adobe Reader application is open a second PDF can not be opened. Oddly enough, double clicking on the PDF will add the PDF the to Recent Files within Windows File Explorer but it does not create a new tab or window within the Adobe Reader application.
This article provides a solution to the issue where you can not open multiple PDF’s within Adobe Reader.
One way to resolve the issue with Adobe Reader only opening one PDF file at a time is to temporarily disable “Protected Mode“. We would not want to do this unless we are only opening PDFs from trusted and verified sources. Otherwise see the other PDF Reader Solution provided below.
To disable Protected Mode at startup click on Menu > Preferences from the Adobe Reader application window.
Then select Security (Enhanced) and uncheck the “Enable Protected Mode at startup” box. Click on “Yes” when the confirmation box appears then click the “OK” button.
See animated image below for a complete walk-through:
I also tried leaving Protected Mode “on” and adding the locations of the files to the Privileged Locations list, but this also did not allow multiple files to open.
I’ve tested this version of Adobe Reader with previous versions of Windows and did not have the issue, so it seems to be something in Windows that Adobe Reader is not playing nicely with.
Another potential work around which does not require the disabling “Protected Mode at startup” would be to open a subsequent PDF from Menu > Open. Then go to the Home tab and double click on any PDF from the Recent Files section. Alternatively you can try dragging a PDF directly into Adobe Reader application window.
I hope my article on resolving the issue where you can not open multiple PDF’s in Adobe Reader has helped you. I welcome your thoughts, questions or suggestions regarding this article.
Let me know if you found any errors within my article or if I may further assist you by answering any additional questions you may have.