I have an issue with a user where their primary Exchange calendar is not syncing with their iPhone. They have another calendar (personal events) in their profile that is syncing correctly.

So far, I've tried restarting all Exchange services on the server and I tried deleting the iPhone exchange profile and re-adding it. Neither step yielded any results. I also attempted creating a third calendar with some dummy events, which did sync properly to the iPhone.

I also confirmed that the calendar in question does indeed have events by deleting offline content in Outlook and re-syncing the events from the server.

What could be causing this, and how can I resolve it?

  • How large is the user's mailbox?
    – CIA
    Nov 20, 2015 at 20:28
  • @CIA Huge, but email is not affected. And it was working as of ~2 weeks ago, with no significant changes made to their mailbox/size. Currently their store is ~30GB
    – user189133
    Nov 20, 2015 at 20:29
  • Mailbox size affects just about everything in Exchange 2003. Can you test the calendar with a test account that has a empty mailbox? Do you have a cluster environment in place or just a single server? Also, do you have ActiveSync logging enabled? Can you pull anything from the logs that relate to the user in question?
    – CIA
    Nov 20, 2015 at 20:42
  • I'll attempt your first suggestion. This is just a single server with frontend. I'm not sure about activesync logging but I'll check.
    – user189133
    Nov 20, 2015 at 20:52
  • @Moses, you are assuming that it's a problem with exchange, but have you already checked the client side? Just a thought...may have look here: (support.apple.com/en-us/HT203521)
    – Diamond
    Nov 21, 2015 at 22:04

1 Answer 1


I have seen email accounts stop syncing on both Android and the iPhone 5. Deleting the account on the phone and adding it again does often correct the issue for us.

However, since you have already tried this, verify that the mail days to sync is set to something reasonable like 1 week. I have seen strange issues when our users attempt to get all of their mail onto their phone.

Once that is set, turn off WiFi and see if the account will sync on 4G. After the initial sync, turn on WiFi and send them another test email.

On the apple discussion boards, one user said that they had to perform the following steps (in order):

Delete the iphone account for exchange

Settings -> Mail, Contacts, Calendars -> Exchange account -> Delete Account

Reset Network Settings

Settings -> General -> Reset -> Reset Network Settings

The phone will reboot.

After the phone reboots, don't add any WiFi networks, until after the exchange account is set up again

Settings -> Mail, Contacts, Calendars -> Add Account

Fill in all settings and ensure all have √ marks

If email syncs, add a WiFi connection and enable it, then send a test email to see if email is delivered and sync'd properly.

  • The issue isn't with mail - only with one particular calendar.
    – user189133
    Nov 20, 2015 at 14:55
  • Either way, these steps did not resolve the problem with the one calendar not syncing.
    – user189133
    Nov 20, 2015 at 20:10

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