"This library is currently being used by someone else. Try opening it again later"

trust me – as this can be caused by multiple issues!  

contact Technical Support directly

1-800-336-4474 option 4 then 1

or

https://support.clarivate.com/Endnote/s/technicalsupport?language=en_US

Best Regards,
(per Tony M.
RS
Clarivate Analytics

Product Specialist
Phone: +1 800 336 4474
clarivate.com)