Someone tells you they sent an email, and it is not in your inbox. You find it in Deleted Items, or in a folder you have never used, or not at all. Mail almost never disappears on its own. Something moved it, and there are only a handful of things that can.

Try this first

1. Check your rules, before anything else. In Outlook on Windows, click File, then Manage Rules and Alerts. In Outlook on the web, click the gear icon at the top right, then Mail, then Rules. Read every rule in the list, including ones that are switched off.
2. Look for rules you did not create. Rules that move mail to Deleted Items, to RSS Feeds, to Archive, to Conversation History, or to a folder with a blank or single-character name are the ones to be suspicious of. So is any rule that marks mail as read and files it away.
3. If you find a rule you did not create, stop and report it. Do not delete it, and do not keep working in the mailbox. Ring us on 03 9028 4358. A hidden rule is one of the standard signs that someone else has access to a mailbox, and the rule is usually there to hide replies from you while they run a scam in your name. We need to see it before it goes.
4. If the rules are all yours, turn one off and test. Untick the rule you suspect, ask a colleague to send you a test message, and see where it lands.
5. Check Focused Inbox. If you see two tabs above your message list saying Focused and Other, mail is being sorted into two piles and the Other tab is easy to miss. Right-click any message and choose Always move to Focused, or turn the split off entirely under View, then Show Focused Inbox.
6. Search the whole mailbox, not just the inbox. Click in the search box, then change the scope dropdown to All Mailboxes or Current Mailbox. Search for the sender's address rather than the subject line.
7. Check Junk Email. Right-click anything found there and choose Mark as not junk so it stops happening.

If that didn't fix it

If your rules are clean, the junk folder is empty and searching the whole mailbox turns up nothing, the message may have been stopped before it reached you by a rule that sits above your mailbox and applies to the whole business. You cannot see those, but we can. There is also a chance it never left the sender, in which case they will have a bounce message.

When you log the ticket, give us:

• The sender's full email address and the date and rough time they sent it.
• The subject line if you know it.
• Whether it is one sender, several, or everything.
• Whether other people in your business have the same problem.
• Whether you found any rules you did not recognise.

Why this happens

Four causes cover nearly all of these. An inbox rule someone set up months ago and forgot. A rule that applies to the whole business, usually created for a good reason and never removed. Focused Inbox quietly splitting your mail in two. Or someone else signed into the mailbox, hiding their tracks.

The last one is the reason we ask you to check rules first and to tell us straight away rather than tidying up yourself. If a stranger has been in the mailbox, the rule is evidence, and how long it has been there matters. Reporting it early costs you a phone call. Finding out three weeks later, usually when a customer says they paid an invoice you never sent, costs a great deal more.

Still stuck?

Log a ticket at portal.yougrowit.com.au or email support@yougrowit.com.au. If it is stopping you working right now, call 03 9028 4358.

Support hours are Monday to Friday, 8:30am to 5:30pm Melbourne time, excluding Victorian public holidays.