All of a sudden, whenever I open a document inn Adobe Acrobat XI PRO - I have a black screen. It is not the Accessibility in Preferences- if I export the document to a word file, there is no black screen. I don't know what to do, I've looked at the views and the background, but nothing seems to change it.
When you say "black screen", what exactly do you mean? Is all of the Acrobat UI black? Do you still see the toolbars and e.g. the "Tools" area on the right side? Is it just the document view that is black? Do you see any details in the document?
If you are sure that this is not caused by the accessibility settings, I would repair the Acrobat installation (that is available on the Windows version of Acrobat in the Help menu), and if that does not help, I would run Adobe's Cleaner tool and re-install (Download Adobe Reader and Acrobat Cleaner Tool - Adobe Labs ) - this again is only available for the Windows version.