This bug has been reported quite often and is still there. I debugged this one and here are my findings: The reason behind this is the range optimization, that sorts requested http ranges in ascending order (done in OFS/Image.py and ZPublisher/HTTPRangeSupport.py) The acrobat plugin is definitely unhappy with these sorted ranges that Zope uses for creating the response. Acrobat expects the ranges in the very same order it has requested them. RFC 2068 is unclear on this point, so I would consider it at least questionable whether range sorting is allowed. As some clients do not work with sorted ranges it should probably be considered as evil. I suggest the following bugfix: http://www.zope.org/Members/must/Zope_HTTPRange-patch This patch applies to Zope 2.4.4 and inhibits any range optimization. The Acrobat plugin will display pdf files without any problems after applying this patch. Markus Stoll -- E-Mail: markus.stoll@junidas.de Web: http://www.junidas.de/