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I am having problems viewing documents in Adobe Reader 9. Mac users are downloading a writable PDF from our system, saving it with content, then uploading it back to the system. All Mac users' documents are coming back blank unless clicked on. For some reason, all Mac PDF's are appearing blank . . Also when a mac user goes to close document if does not ask if you want to save or not.
This is due to Apple's improper handling of pdf files with its Preview Application. This will not happen if your users use Adobe Reader. You can find a fix for individual files here: http://kb2.adobe.com/community/publishing/885/cpsid_88564.html