If your group needs to share access to attachments as well as reference data, or for some reason cannot use EndNote Sync, needs to share attachments with more than fourteen others, then another option is to put a read-only copy of the library on a network drive so that an unlimited number of people can access it at one time.
One person should be in charge of the master library, and keep it on their own computer, then periodically put a read-only copy of the library on the network drive.
Your network administrator can set up folders on the network drive with security settings to allow only one person to add files while everybody else has read-only access.
When you open a read-only library, you will see a message:
The file 'Example.enl' is locked or in a locked volume. No changes will be saved.
Click the OK button to open the library.