When you try to digitally sign a PDF in Adobe Acrobat 8 or 9 on Windows, the application returns the error message "Creation of this signature could not be completed. Platform Exception." The error message is followed by one of these expressions:
- "Object already exists. Error Code: 2148073487"
- "Keyset does not exist. Error Code: 2148073494"
- "Key not valid for use in specified state. Error code: 2148073483"