Many people have experienced issues with syncing their Microsoft exchange email with their iPhones since the new iOS 6 update. We came up with a temporary fix until apple releases an update to resolve the issue. It works for most people but not all. Here are the simple steps to fix it:
1) Go to Settings > mail, contacts, calendar,> scroll down to “Show” and change that to 200 or 500 recent messages.
2) You also have to check how many emails you have in other mailboxes. If that number is really high, lets say more than 500 emails, in order for the fix to work you also have change how many mails to sync on each mailbox from no limit to 1 month or even less.
3) if your iCloud mailbox has way too many mails in inbox this fix may not work for you. It will work if you turn off iCloud mail in settings. This will not delete your mail. You will have to live without iCloud mail until apple fixes it.
4) Go to settings > notifications > Mail and check each account if notification center is on
5) Go to settings > Mail, Contacts, Calendar > Fetch New Data > Turn push off and back on again for each mail account.
Hopefully this will fix your iPhone issues with Microsoft Exchange. We hope we were able to help.