There are two workarounds, depending on your use case:
If you manage or administer software that automatically generates PDFs, modify the way the PDF is produced. Make sure that no extraneous bytes appear before %PDF at the head of the file.
PDF consumers: Enterprise admins and end users
If you are a customer or an enterprise IT professional, you can disable the header validation on machines by setting the appropriate preference. You can set this preference per user in HKCU or at the machine level for all users in HKLM. You can use a similar method on Mac OS by modifying the same plist preference. If the AVGeneral key does not exist, create it manually.
The HKLM path is generically:
For example, to change the behavior for Acrobat 11.0, create a DWORD at this location: HKLM\SOFTWARE\Adobe\Adobe Acrobat\11.0\AVGeneral\bValidateBytesBeforeHeader=dword:00000000
The HKCU path is generically:
For example, to change the behavior for Reader 10.0, create a DWORD at this location: HKCU\SOFTWARE\Adobe\Acrobat Reader\10.0\AVGeneral\bValidateBytesBeforeHeader=dword:00000000
Always change the product and version number in the preference path to match your installation. This method allows the PDF to display on machines you control.