When you delete a reference from a group, it is moved to the Trash and is deleted from all groups in your library.
If you want to remove the reference from a custom group without deleting it from your library, see Removing References from a Custom Group.
To delete a reference from your library:
Highlight the reference (or multiple references) in the reference list of the Library window.
Move References to Trash.
The references are now moved to the Trash group. The Trash group is a temporary holding place. The references are no longer in your library and cannot be cited or searched, but they have not yet been irrevocably discarded. If you change your mind, you can still drag a reference from the Trash back to the All References group to bring it back into the library.
When you are absolutely certain that you no longer want the reference(s) you have moved to Trash, select the Trash group and then go to the References menu and select Empty Trash.
Display All References to continue working in your library.
Warning: When you delete a record from a smart group, EndNote also deletes the record from All References without warning. To restore the reference, go to Trash, and then right-click to bring up a menu. Select Restore to Library and EndNote returns the reference to the smart group.