In the previous releases, it was possible that a PDF file would not open in the default handler if other applications were open. For example, even if Adobe Reader was set as default handler for PDF files, the PDF files would open in Acrobat if Acrobat was installed and running. This could lead to issues, especially for sandboxing applications.
In this release, the PDF files open in the default handler even if other applications that can read PDF files are open. In the example cited earlier, the PDF now opens in Reader, even if Acrobat is running.
To implement this feature, there has been a change to the DDE naming convention—the DDE server name has been made unique for Acrobat and for Reader. The new naming convention is as follows:
Acroview{A|R}{MajorVersion} where {A|R} refer to Acrobat and Reader respectively.
For example, the name is AcroViewA10 for Acrobat X and AcroViewR10 for Reader 10.
For connecting to previous versions of Acrobat and Reader, the DDE connect string name continues to be “acroview”. You can get the correct name by using the “DDEAPPNAME” macro defined in WinAppSemaphore.h.
NOTE: Any scripts that have hard-coded references to the DDE name will have to be updated.
Please see the Developers Guide to Acrobat X in the list of guides to the left for the most current information about developing with Acrobat X.


I might have clients using any number of versions of Adobe Reader. From a VB application, how can I find what DDE server name to use?
I’m guessing a try/catch should do it.
J-
I cannot open my pdf files although i have Adobe x correctly installed.. i keep getting fatal error notice. I have the option to open with IE or Adobe reader and when i selct reader the pdf file does not open/where in my computer should the the reader be sited (hard drive?) for it to correctly run and open pdf files?
You might try contacting customer support or the user to user forums, there’s really no way to debug this issue via blog comments.