This happens far too often and is completely understandable. I am sure I would have done it by now if I used our distribution lists. Every few months or so it seems like somebody here in the office goes to edit one of the lists to keep them nice and clean (thank you) but when they go to delete a user from the list they accidentally delete the entire list itself. You can see why below:
I completely understand why they would immediately go to delete group instead of remove member. You see the big X signifying delete and just assume that’s what it will do when you have the user highlighted. I know how to recover the lists when they do delete them. You have to hunt through the deleted items and find it. If you sort by date it will sort the list based on the date it was created, not when you deleted it. Click on the group and drag over to the left where it says contacts or in our case go to folder list view and click and drag it to the appropriate contacts list under public folders.
The next time the person tried to send an email to the group they would get an error that said “unexpected error.” *sigh* So I finally got the bright idea to start typing in the group name into the To: field to make the auto-fill show up and delete that entry. I clicked the To: button and added it that way, sent the email and it worked. For some reason the auto-fill entries break if you delete the group and restore it. There must be some way outlook is identifying the auto-fills and when you restore the group it gives it another ID number or something.