This has only ever happened three times in my adult life.
Receiving up to 2,000 emails a month, it's very rare to get even near a zero inbox. I have beaten my personal best today in that, this third time, it stayed empty for a whole 20 minutes. I think 'zero inbox' should be suggested as a discipline at the next Olympics !!
Previously this year I wrote an article on the best strategies to reduce your inbox, and this month I have done exactly that.
At the beginning of the month, I had 800 in the box, so sorting them into categories, deleting all the junk, filing everything I've read (I never delete anything). Then categorising and dealing with things in batches, I completely sorted stuff in 10 days (about an hour a day).
One of the biggest issues remains spam, which even with GDPR finds well-known companies still spamming me, even though I have not sign up to their list. They bank on the fact that I like so many others won't spend the time to report them to the governments Information Commissioners office. So it's a normal unsubscribe, unsubscribe, unsubscribe. This works because the companies usually send through an email sending platform like MailChimp, SendGrid, etc. etc. Once they get an unsubscribe the provider takes you off the list, not the company. I've found over the years this is by far the most effective way to stop spam from big companies.
Anyway, the task now is to employ is to spend half an hour early morning to kill off anything that can be dealt with quickly and then through the day grouping tasks to deal with everything else that's left.
We'll see how this goes, but for sure I've never been as determined to remain on top of this issue than now.