Emails missing in EAS but fine in IMAP
Problem reported by Jim Heinz - 9/3/2026 at 6:48 AM
Known
Im using old outlook (office 365) and Im missing email in EAS using outlook but I see them in outlook using IMAP.  

What could be the problem?
Derek Curtis Replied
Employee Post
If you're using EAS for a desktop version of Outlook, that is the problem. EAS is, almost exclusively, for mobile synchronization now. For desktop, the standard POP/IMAP connections are best, with MAPI being the best choice for full synchronization. There was a time when EAS would mostly work for desktops, though it was inconsistent. That's just gotten worse. 
Derek Curtis
CCO
SmarterTools Inc.
Jim Heinz Replied
How can I setup MAPI to work?  it is never an option for me.
Jim Heinz Replied
Switching to IMAP until I get a new wildcard cert...

Thanks
Tony Scholz Replied
Employee Post
Tony Scholz
Lead Network/System Administrator
SmarterTools Inc.
Thomas Sangster Replied
The issue may be related to differences between EAS (Exchange ActiveSync) and IMAP synchronization. IMAP may display emails that are not being synchronized or shown correctly in the EAS account because of folder mapping, synchronization settings, server-side filters, or account configuration.

Try refreshing the mailbox, checking the synchronization settings, and confirming that the missing emails are stored in folders accessible through EAS. If the problem persists, remove and reconfigure the account after ensuring you have a backup of important emails.

ß Replied
To force MAPI, I sometimes have to temporarily disable EAS for the account I'm trying to setup in Outlook. Otherwise, it seems Outlook tries EAS and uses it.

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