We made many PDF files available on our Web site. In the past few weeks we noticed that users who were using Acrobat Reader X and Internet Explorer 8 or 9 were not able to view some PDF files. Basically, when they clicked a link to display a PDF file, the screen would be cleared and the status bar showing "Loading ...KB/...K/B" would be displayed. The status bar would move a bit and then got stuck. The PDF file would never be displayed. Sometimes, my users could click the Back button to go back the previous Web page and sometimes they had to close or kill the IE window. Small PDF files seemed to be fine. I was able to repeat this problem on PCs running Windows XP and Windows 7. I also tested clicking the same PDF files with PCs installed with Acrobat Reader 9 and I was not able to cause the problem to occur, so I am pretty sure that this problem is related to Acrobat Reader X. I also noticed that if I unchecked the "Display PDF in browser" option in Acrobat Reader X so that PDF files would not be displayed inside the Internet Explorer window, I would be able to view all PDF files without any problems.
I also did an experiment by resaving many PDF files using Acrobat Pro (Reduce File Size...) to be compatible with Acrobat 8 or above. I was able to open these PDF files using Acrobat Reader X but when I used a PC with Acrobat 9, it would get stuck instead. Most of my PDF files were created a long time ago and we usually made it compatible with Acrobat 5 or above.
I saw that some people reported some problems with Acrobat Reader X but I did not see a solution except uninstalling Acrobat Reader X and installing an old version of Acrobat Reader instead. Anyone has any ideas why this is happening and how to fix this problem?