We recommend that if a customer has upgraded to EndNote X9.3.3 on OS-X-10-10-Yosemite-and-10-11-El-Capitan that they install the version of the tools available in the link below.
http://download.endnote.com/downloads/plugins/Cite%20While%20You%20Write-19.1.dmg
If you do continue to have trouble after installing the above version of the tools or want assistance installing the tools please contact us for assistance.
FAQ category