PDFs and Internet Explorer. The combination of Internet
Explorer and Acrobat is not always trouble-free - particularly
under https or using older versions of Internet Explorer. It can be
difficult to know exactly where the problem lies because there is
an interaction of the Operating System, Internet Explorer and
Acrobat. Any of these can be the cause.
Sometimes, Internet Explorer may get 'stuck' on a particular
content type and insist on displaying your PDF as HTML. In this
case, you will see random text starting with %PDF. Sometimes, this
can happen if you stream PDF data to a window which was previously
Sometimes, server-side debugging results in extra data being
inserted into the content stream. While this may not matter for
HTML, it will corrupt binary documents like PDF.
Sometimes, your code may inadvertently insert extra data into
the content stream. Again, this will corrupt the PDF. Error
messages are a common cause of this kind of corruption.
HTTP compression may result in PDF streams being compressed
before they are returned to the browser. While browsers are able to
deal with this type of compression, Acrobat may not be able to. You
can see whether this type of compression is being used by examining
the headers returned to the browser using a tool like IEWatch. If
you are using IIS 6 compression, you can disable it on a
page-by-page basis using the IIS Metabase Explorer from the IIS 6
For testing purposes, you may wish to change the
content-disposition from 'inline' to 'attachment'. This will allow
you to download the data rather than viewing it in your browser.
You can then check the downloaded document using Acrobat or a hex
Alternatively, if the problem is that PDFs seem to be cached,
you may wish to check the 'Enable Content Expiration' checkbox you
will find under the Web Site Properties.
We would suggest two steps:
- Your first step should be to eliminate ABCpdf as the cause. Why
not save the PDF to disk at the same time as sending it to the
client? That way you can establish that the PDF is fine. If you
want to take it further, you can then read the PDF data from disk
and stream it direct to the client.
- The example site streams PDF data direct to the client. So
install the example site into a new virtual directory, and
establish whether the same issue exists for the example site. If it
works, then it's simply a matter of moving your current code base
and the example site code base towards each other until you find
the cause of the problem.