A year ago, a prior administrator created a custom field 'Internal ID' in the Account object with a field type of Auto Number. However, he did not check the "Generate Auto Number for existing records" checkbox. As a result, I have 79 Account records with no Auto Number.

I need to get an Auto Number assigned to those 79 Accounts. The problem is that the option to "Generate Auto Number for existing records" only appears when the Auto Number field is first created.

I've seen a method described where you change the Auto Number field to text and then back to Auto Number. But the details of using that method are vague, and I can't tell if I will lose the Auto Numbers that are already assigned. I absolutely can not lose the Auto Number that has been generated for the other 40 thousand Accounts. If I lose the existing auto numbers, I can probably kiss my job goodbye.

Anyone have any suggestions? Thanks!