The first time a citation is formatted, EndNote uses information from the unformatted citation to look in the open library and find the corresponding reference. If you later reformat, EndNote again looks in the library for that reference. If the reference has been deleted from the library, EndNote takes the reference information from hidden field codes in Word (the Traveling Library).
So, if you deleted a cited reference from the library, the required information is still available in the hidden field codes surrounding each formatted citation—even though the reference is no longer in the library.
However, an unformatted citation is a temporary placeholder. If a citation is unformatted, and you have deleted the corresponding reference from the EndNote library, EndNote will not be able to find the reference information for formatting.
If you add the reference to the library again, it will be assigned a different record number. You would need to re-insert the citation in Word.
EndNote assigns a unique record number to each reference as it is added to your library. These record numbers appear in temporary citations to ensure that the correct reference is used when the paper is formatted:
{Argus, 1991 #11}
The record number for a reference is also visible in the title bar of the Reference window.
Note that:
EndNote automatically assigns a record number sequentially to each reference as it is added to a library.
If the same reference appears in two different libraries, the record numbers will most likely be different.
Record numbers are never reused or reassigned within a library. When you delete a reference, the corresponding record number is never used again in that library.
You cannot modify or reassign record numbers.
We recommend that you not rely on EndNote’s record numbers as a means of filing or numbering your office reprints, because you have no control over this number. Instead, enter your own unique number into the Label field, or any Custom field, and use that number for your reprints.
If you add the reference to the library again, it will be assigned a new, different record number, so EndNote still will not be able to find it when formatting your paper. You will need to reinsert the citation into the paper using the new reference in your library.