Outlook.com stops syncing with Outlook 2013

I've configured my Outlook.com account in Outlook 2013 as an Exchange Active Sync (EAS) account.

In a previous post you mentioned that unlike Outlook Hotmail Connector accounts, which syncs on a schedule, mail for EAS accounts in Outlook 2013 should arrive almost instantly (Direct Push).

This is indeed the case for a while but when I have Outlook open for a longer period of time, my Outlook.com account stops synching with Outlook and I have to press the Send/Receive button to get my new mail or restart Outlook

How can I prevent Outlook from breaking this sync and continue to collect my email directly from the server as it arrives?

Outlook.com Exchange ActiveSyncThe EAS protocol indeed should give you a near instant delivery experience for new emails.

This is achieved by creating a session which holds an idle connection to the server for a specific interval, also known as a heartbeat.

Unfortunately, under some circumstances this heartbeat may stop. Luckily, it is quite easy to revive it as well.

Heartbeats and timeouts

Due to network idle connection timeouts, usually configured on firewalls, this heartbeat and thus the active session with the server could be closed prematurely. In that case, the following happens:

  • Outlook is unaware of this disconnect as it doesn't expect a response back from the server until a new message arrives or when the heartbeat interval expires.
  • The server thinks the client is offline and will not attempt to push these emails to the client until the client reconnects by itself (Outlook does this by default every 59 minutes).

Pushduration Registry value

If you are in an environment where the Direct Push session gets terminated prematurely by the firewall, you can configure Outlook to create a session with a shorter heartbeat interval by modifying the "pushduration" Registry key value.

Key: HKEY_CURRENT_USER\Software\Microsoft\Office\15.0\Outlook\EAS
Value name: pushduration
Value type: REG_DWORD
Value: <time in minutes>

The best value for this key name is 1 minute shorter than the session time-out configured on the firewall (which explains the 59 minute default as 60 minutes is a common session time-out value on a firewall and an even longer heartbeat interval wouldn't make much sense anyway) .

Note: You can contact your network administrator to find out this value rather than by going by trial and error as indicated below.

Registry key value name pushduration
Set the Base to Decimal to see the time in minutes.

Trial and error

A good trial and error method is decreasing the value with 5 minutes each time until you will no longer experience any disconnects. Make sure you restart Outlook after changing the value.

Another method is to set it to 29 minutes (as 30 minutes is another common time-out value) and if you don't experience any disconnects then, increase the value with 5 minutes each time until you will no longer experience any disconnects.

Warning! Don’t set it too low!

Setting this value lower than 5 minutes or any other value much lower than the firewall time-out isn't recommended as it won't improve Outlook performance.

In fact, doing so will actually increase network bandwidth consumption, decrease battery life and could get you banned from the server by making too many requests in a specific timeframe.

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