Unable to Split Documents - Error message "The file may be read-only, or another user may have it"

Unable to split any documents.  I can rename edit and change the document, but not open and split the documents.  I verified local security, document security I tried copying the document to a new location and PC. I tried 2 different versions of adobe and 2 different computers however when I try and split the document I get an error: The file may be read-only, or another user may have it open.  Please save the document with a different name or in a different folder.