User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8b) Gecko/20050125 Firefox/1.0+ Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8b) Gecko/20050125 Firefox/1.0+ The addressbook case-sensitively collects email addresses. If you send an email, or you receive an email with an address in which even one character is a different case from what is already in your addressbook, it will be stored as a new address. This is confusing and IMO nonintuitive. I've had to delete a couple dozen address entries the past few months because of this. Reproducible: Always Steps to Reproduce: 1. Send an email to someone who is not yet in your addressbook. 2. Change the case of 1 letter in that address and send it again. 3. Both addresses now show up, even thouogh they are (effectively) the same. 4. ??? 5. Profit! Actual Results: Two entries in the addressbook: same address, but different case. Expected Results: Addressbook should have not collected the second address.

I also found this to be true. There is no logical reason to have multiple entries for essentially the same email address. Running version 1.0 (20041206)... Thanks for looking into this.

*** This bug has been marked as a duplicate of 129393 ***

To the best of my knowledge this bug still exists in the main code. To get it fixed please go to bug 129393 https://bugzilla.mozilla.org/show_bug.cgi?id=129393 and click the vote button to raise its level of importance.