DOI field disappears on some references

I have my output style (bibliography template) configured to show DOI links when available for journal articles (EndNote XI). Today, though, the DOI field has disappeared from some references that I downloaded from PubMed. Usually, it’s between the ISSN and Accessions Number fields within the reference, but it’s not there in several references. I can think of a couple ways to work around this for today, but I don’t want to have to use a workaround in the future. Is there a way to manually add the DOI field while editing the reference? Thanks for your suggestions.

In EndNote X1 you would need to manually update the references or redownload them from PubMed in order to get the missing data.

You might consider getting EndNote X8 since it has a feature where you can ask that it Update References and pull in missing information the feature did not exist in EndNote X1.

You could even try the demo version of X8 to test this feature called Find Reference Update and if you decided to not purchase you could go back using EndNote X1 and would not lose the updates.