EndNote X9.3 uses a new database engine so a library created with or converted by EndNote X9.3 will not be able to be opened by any previous version of EndNote on Mac or Windows.
If you are working with one library, we suggest using the Sync feature which would allow you to work on the same library on a Mac and Windows machine.
If you do need to transfer a library that has been converted by EndNote X9.3 to a Windows machine, then we suggest you use the File > Export command to export an XML file which you can import into a new library on a Windows machine.
You would not retain the groups, but you can transfer the pdf files manually to Windows and place them inside the PDF subfolder of the library’s Data folder.
If you have further questions on this workaround until the EndNote X9.3 is released for Windows which is coming soon then please contact Technical Support.
1-800-336-4474 option 4 then 1