Then Endnote uses the record number in the inserted temporary citation.
but sometimes I will sort on the accsssion number field, and show those that are empty, try to update them (to make sure a PMID didn’t come later) repeat and show only those that don’t have an Accession number. Then I use the change/move/copy tool to copy the record number to that field and then (using the same tool) add the preceeding hash to lock in that number, incase it gets messed up later - or I need to share the library with others who do want to sync.
There are older journal papers in my library that don’t have
Before the PMID option, I also routinely sorted on the label field, and have a code of the original record number for all my references. I copy the record number there, and then precede it by by LMW and end with X (as sometimes searches for this field pull partial matches). So I used to use the “label” field as an option. But the accession number is better and if there are a small number of cites that don’t match because I am collaborating – it isn’t a big deal to go thru those, when Endnote prompts me and choose the right citation.