This error can occur due to special characters (non-ASCII) found in the name of the attachment(s) being imported from EndNote.
As a workaround, you can go to your library in Endnote and select a reference with an attachment, then in the right side window, select PDF to view the name of the attachment. If you see characters in the PDF name that you don't see on your keyboard, the file name should be changed. The following steps may be used to change any or all of the attachment names in EndNote.
- Open your library.
- Choose EndNote: Edit > Preferences > PDF Handling.
- Choose your preferred naming of your PDF files, e.g. Author-Year, avoiding long names (>255 characters) or names with no context e.g. many characters/numbers.
- Select Custom. In the Rename Options box, select Record Number. This will rename the selected attachments to XXX.pdf (XXX=Endnote Record Number). Please note, if you have multiple attachments for a single reference, you must also select Secondary and Tertiary in the Rename Options box.
- Click OK.
- Select all references in your library (EndNote: Edit > Select all, or click one reference in your library and use Ctrl+A).
- Choose EndNote: References > File Attachments > Rename PDFs.