Windows Email and Outlook FAQ—Folder Sync Settings

Stacks of envelopes
cocoparisienne / Pixabay / Public Domain

If you use IMAP-based or Windows Live Hotmail accounts in Windows Mail or Outlook Express, those applications can automatically synchronize folders as soon as you go online and download all messages for offline use.

In many cases, this is useful behavior, but Windows Mail and Outlook Express can also download only the headers, not full messages—or not synchronize automatically at all.

This setting can be tweaked per folder, so you can have your Inbox synchronize in full while Windows Mail or Outlook Express only fetches the headers of new messages in some shared IMAP folders, for example.

Tweak Synchronization Settings per Folder in Windows Mail or Outlook Express

To change the synchronization settings for a folder in Windows Mail or Outlook Express:

  • Click with the right mouse button on the folder of an IMAP or Windows Live Hotmail account whose settings you want to change.
  • Select Synchronization Settings from the menu.
  • Choose the desired action:
    • Don't Synchronize if you want no automated synchronization at all.
    • All Messages if you want Windows Mail or Outlook Express to download all messages completely.
    • New Messages Only if Windows Mail or Outlook Express should only synchronize unread mail.
    • Headers Only to download only the message headers automatically. (You can download the complete message upon request later.)

Modern Software

Windows Live Hotmail, Windows Mail and Outlook Express have been deprecated since the early 2010s. The native Mail client for Windows 10 devices does not support per-folder syncing; it'll download all relevant email folders automatically. It will also load full messages, not just headers.

IMAP Folder Subscriptions

The folder-sync settings in the older versions of Windows Mail, Outlook Express and related applications are still commonly supported in many native email clients as well as some open-source webmail solutions. The term most commonly used is subscription—i.e., you "subscribe" to an IMAP folder to see its contents and sync it within that particular email solution.

Some of those applications and webmail tools also allow a headers-only option.

Headers versus HTML

In the late 1990s and early 2000s, it was common to download headers-only folders for IMAP email accounts, because downloading the entire message on a dial-up connection might take an inordinate amount of time. With broadband Internet more widely available, this bandwidth constraint isn't nearly as pressing as once it was.

However, it's increasingly common to set an option to disallow the loading of HTML elements within a message. By disallowing HTML, you'll not only reduce the risk of viruses, but you'll also fight against tracking and data loss. Some spammers, for example, embed tracking pixels in HTML messages that, when the pixel is downloaded from their server, proves that you've opened or read the email—and thus, that your address is "live."

To configure Windows Mail on Windows 10 to suppress HTML by default:

  1. Click the Settings button—a gear-shaped icon—in the lower right corner of the first pane of the Mail app
  2. From the Settings window that slides out from the left, select Reading
  3. Under the External Content heading, ensure that the switch for Automatically download external images and style formats is set to off