Problem
I opened Adobe Reader on a M$ Win* 7 desktop in a library so as to print a PDF file. I couldn’t understand why this window kept popping up.
Result
Lacking time, I won’t find a solution for this problem.
If I choose to ignore this window, then the printing job can still be carried out. Therefore, I just waited until the document was printed. Then I closed Adobe Reader.
Remarks
I choose Sumatra PDF since it is licensed under GPL.