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Find Your Missing Email

This article distinguishes between email servers and email programs (email programs are also called email clients). Cornell's email server is Exchange 2010 from Microsoft. Email clients are programs such as Outlook, Mail, and Thunderbird that run on your desktop or mobile phone, and access mail on the mail server. Outlook Web App is also a mail client, but a web-based one that you access through a web browser. An analogy using the phone system is that the telephone on your desk is a client, and Verizon is the server.

Missing email (or missing folders) is one of the most distressing things that can happen to an email user. We get a number of such reports each month. This article describes what we've learned through helping people find their lost items.

Many conversations with upset users start one of two ways: "Your mail server lost my mail" or "Can you restore my mail?" Let's deal with those first.

"Your mail server lost my mail!"

Actually, that has never been the case in any of the reports we have investigated. The mail server handles the actual delivery of new mail to an Exchange account, but all other changes and actions are made through an email program such as Outlook. It's always an action by one of these programs that makes mail disappear.

"Can you restore my mail?"

Unfortunately, no. We back up the Exchange database as a whole, as a protection against disaster. It's impractical to restore an entire Exchange database to restore a single mailbox. The good news is that Exchange doesn't really delete mail items until 30 days after you've told it to. It first keeps deleted items in a special folder called Deleted Items, (some programs label this as Trash). After the Deleted Items folder is emptied, items are held in a dumpster for 30 days, and you can usually find missing items there. See our Recovering Deleted Items page for detailed instructions.

Remember to look or take action on every computer or device you use to access your email. Exception: a computer or device where you only use OWA.

Here are the most common ways to lose email, and what to do about them.

[affects Outlook 2010 (Windows)]

Outlook comes with a feature called AutoArchive, which offers to keep your mailbox clean by moving older items to an archive folder. It will helpfully ask you if you want to do this. It will even try to make it sound like a good idea. The problem with autoarchive is that it creates the archive folder on the Windows computer you're using at the time, NOT on the email server. If you access your email from more than one computer, or your mobile phone, or from Outlook Web App (OWA), you won't see the archived email from those other locations. A very common scenario is to accidentally click "Yes" when the autoarchive prompt first pops up, for example, on a newly installed home machine, and then have mail apparently disappear when that machine stores all the older messages locally. If you use Outlook 2010, the first prescription for missing mail is to disable the autoarchive settings on every machine you have. Don't forget that old laptop that you only turn on once in a while when you take a trip.

AutoArchive is also a suspect when you're using a shared mailbox. For instance, Wendy and Wallace could be sharing a mailbox for conference registrations. Wallace wants to use autoarchiving for his own mailbox. However, if he opens the shared registrations mailbox within his primary Outlook profile, the autoarchive settings will happily archive that mailbox as well. As far as Wendy can tell, all that mail suddenly vanished from the shared mailbox. Wallace doesn't know anything is wrong, because he can still see all the mail. The solution is to open the shared mailbox as a secondary account, using *these* instructions. And if you must move mail to local folders to manage your mailbox size, it's often better to do it manually, so you're aware of exactly what you're moving.

Turning off AutoArchive

Click the File tab, click Options, click Advanced. In the AutoArchive section, click AutoArchive Settings. Remove the check next to Run AutoArchive every X days (the first thing in the dialog box). Click OK twice (to close both dialog boxes).

Database corruption
[affects Outlook 2011 for Mac]

Outlook on the Mac has a history of problems with the underlying database that organizes the local copy of your messages. It may sometimes refuse to start, saying the database needs to be repaired. In some small number of these cases, Outlook has lost local copies of messages, and then deleted the messages from the server as well when synchronizing the account. 

Conversation View
[affects all Office 365 clients]

If your messages appear to be out of order, or some messages (especially replies) go missing, you may be in Conversation View. This groups together all messages in a thread (that is, those messages with identical Subjects). 

[affects older clients and some mobile phones]

POP is an older protocol from the era of small mail servers. It downloads the entire contents of your inbox to your computer. When you check your mail from another computer or device, this can make it look like all the email has disappeared. A common accident here is to start up an old client that you haven't used for a while, and later find that all email is gone from your other clients. If you have switched to Outlook as an email program, but have recently started up an old copy of Eudora (perhaps to find an ancient message you received in the Eudora days), take a look at Eudora to see if it has claimed all of your email for itself. If your program cannot use one of the native Exchange protocols (MAPI, Outlook Anywhere, Exchange Web Services, or ActiveSync), use IMAP (a protocol that doesn't move messages off the server) for the connections.

Rules or Filters
[can affect any email client]

Most email programs implement rules for automatically processing mail. Some of them, such as Outlook and OWA, can also set up rules on the Exchange server so they can be executed even when that program is not running. (Rules are called client-side or server-side depending on where they run.) Rules can move email items to unintended places, including the trash. Or a rule intended for one type of message can accidentally apply to other types. Rules are also not compatible between different email programs. Don't try to set up a server-side rule in one program and change it in a different one. Don't try to run client-side rules on more than one email program. If you're dealing with missing email, turn off all rules on both client-side and server-side (using OWA), and then re-enable them one at a time, checking for proper operation.

Synchronization errors
[affects mobile devices]

Most mobile devices work differently from traditional mail programs. They attempt to synchronize changes made on the device, possibly while out of contact from the network, with the mail on the server. Once in a while, a newly set up mobile device will try to overwrite the email on the server with an empty mailbox. If your mobile device has the option, make sure it is set for server changes to take preference over changes on the device. (The wording of this option will vary from vendor to vendor.)

Compromised account
[can affect any email client]

If a hacker has stolen your NetID and password, sometimes they will delete email to cover their tracks, or to make room for the replies to the 100,000 pieces of spam they just sent in your name. This is rare, but it does happen. If email disappears and there have been other signs of suspicious activity, this is worth investigating. The IT Service Desk can get you in touch with security experts to verify if this has happened to you.

Local PST file
[affects Outlook 2010 (Windows)]

It is possible in Outlook to designate a PST (mail folder database) on your computer as the primary storage for your account. Outlook will download all arriving mail to this PST. The symptom of this setup is being able to see all of your mail through Outlook on that computer, but not on another computer, and not through OWA. This is not the default setting if Outlook is set up with your Exchange account as the first account. However, if you first set up a Gmail or other external email account in Outlook, a PST file is the default destination. If you then add your Exchange account to this profile, you're setting up local email delivery. This has the same "gotcha" with shared mailboxes as Autoarchive, above.

The solution to this would be to set up a new Outlook profile with the Exchange account first (see the two bulleted links directly below this sentence), and then open the PST file within that profile to give you access to the previously stored messages (see the next section of this page).

Creating a New Profile in Outlook 2010

Closed PST file
[Outlook 2010 (Windows)]

One report of missing mail involved a PST file used to store items with large attachments. When open, this looks just like another mail folder, and the owner had forgotten that it was not stored on the server. Wanting to find out how large the folder was, the owner right-clicked on the folder name, and selected Properties from the context menu. The folder seemingly vanished. It was later reconstructed that the user had missed the word Properties in the menu, and accidentally clicked the word Close directly above it. A one-pixel difference in clicking caused a very different result.

The solution to this is to locate the PST file in your Documents folder, and use the Open menu to re-open it.

Click the File tab. Click Open, then click Open Outlook Data File. Browse to your PST file (the dialog box should open to the correct directory and show you a list of available PST files), click OK. That data file should now appears in Navigation Pane.

Drag & Drop errors
[can affect any email client]

A frequent culprit for missing folders is the drag error. When intending to select or move a mail item, it can be easy to accidentally drag one folder inside another folder. Some trackpad devices and touch screens can make this type of error quite easy. If you're missing a folder, try expanding other nearby folders to see if the missing item has been dropped in a hidden place.

Shared mailboxes
[can affect any email client]

In any shared mailbox situation, where multiple people access a mailbox at the same time, the number of opportunities for side-effects are multiplied. All of the above scenarios must be investigated for *every* device used by every person who can potentially access the mailbox. Sometimes it is necessary to remove all but one user (and that user from only one location) to stabilize the situation, then add users and devices back one at a time until it is determined which combination causes the problem.