I'm trying to get rid of unread mails older than 5yrs. So I first enter a search "is:unread" and when that list is shown, select a custom date-range with end date of "2016/12/31".GMail then shows 50 of those and provides a possibility t o select all conversation matching this search. After clicking that option, the msg says "All matching conversations are being selected." (Hopefully translated this correctly from german UI).
So, theory has it that I can click the trashcan to delete those message once they are selected.
My question is: will the status msg actually change when the selection has completed? I've given it > 24hrs - and yet a "Delete" only removes around 3-4 monmths (approx. 3k msgs). So I assume that waiting longer will select more - but otoh I can't believe that it should really take so long! (Ok, admittedly, my mailbox has approx. 90k unread msgs - but still it seems to take incredibly looong time). Could I achieve this using another approach?