I'm trying to add a prefix to the tranid/ document number on some estimates but don't want to update all estimates. I found I can only do this via CSV if I allowed override on the Set Up Auto-Generated Numbers page. However, I don't actually want a user to be able to override the document number. If I set the field as inline text on the estimate form so it's not editable, does anyone know of any possible issues I can run into? Basically I don't want it to be editable and I don't want duplicates.

Try by workflow based on saved search criteria

CSV works great. Just don't want to allow override for anyone except by CSV import.

Ok use Allow override and use workflow before record load and disable the field tranid

Yah, I understand that. But the inline edit field type works as they aren't able to edit it

ah ok sorry I read wrong but for me if the field is inline normally they will not be able to modify it unless they have a role with which they can make the field normal

Correct.

use a custom form that role