IOS13 Mail outlook.com duplicate sent items

I have the same problem on my iPhone 7 running iOS 11.4.1 for a long time. I have 3 account: iCloud, Exchange (Microsoft) and Outlook. The latter is my private one and the one who gets duplicate on 'Sent' mailbox. Really annoying.

Not yet, it seems to a major problem which Microsoft and Apple are apparently arguing over who is responsible. Has to be Apple as my iPhone worked fine until I upgraded to 13.2!!! I await a solution or an upgrade

This has been going on for a month. I tried numerous fixes to my hotmail email accounts including removing the mail app on my iPhone 6. I had numerous discussions with an Apple tech incl 8 hours on and off one day with him remotely accessing my phone. Issue is definitely a Microsoft vs Apple problem. Acknowledged that when IOS 13.1 was designed fixes that were made didn’t include hotmail. Doesn’t appear to be a problem with gmail and yahoo emails.

I used to have that issues for ages with outlook.com. That is not Apple problem, that’s outlook. There is a similar discussion on outlook forums too. So I was advised tobuse exchange instead of IMAP with outlook. On my mac it solved that issue, on iOS instead, it did not. And if I delete the duplicate entries on iPhone, they disappear completely from Outlook.com and my mac. Basically I can see a sent message on iOS, if I open the conversation it even says ‘found in exchange sent folder’ but if I go on outlook.com website there is nothing in the sent folder regarding that message.

I don’t buy that it’s not an apple issue. Too much coincidence that problem has only arisen since upgrading to ios13. No issues with my gmail account on any device, just my outlook. Maybe everybody’s partially responsible but at least one somebody must have done at least one thing to mess up something that worked perfectly before. Come on guys, just get it sorted!!

Actually, it's turns out that the source of the duplication is in macOS. I notice that all the emails that I sent from my iPhone (iOS 11.4.1, has 'Sent from my iPhone' at the end) didn't duplicate. It only gets duplicate when sent from macOS mail app.

I am providing a solution that worked a few years back in the hope that someone intelligent (i.e. not me) can extrapolate a solution. A few years back this exact same issue arose. The solution at that time was to go into Settings>Mail>Accounts then select the problematic account (in this case Exchange), scroll down to Advanced, click on Sent Mailbox (it might say Server) and then unselect Store Sent Messages on Server.

In the current iOS 13, there are no Accounts accessible in Settings>Mail as far as I can tell. However, Settings>Passwords & Accounts is the equivalent, but in the Exchange account>Account>Advanced Settings the only thing I see is Store Drafts on Server, which would not seem to be the issue for duplicate sent items in iOS 13.

Also, I am completely ignorant of the impact of not storing sent items, or drafts, on the server.

I implemented a solution for the iPhone, which I read elsewhere, that has been working so far: On iPhone, Settings>Passwords & Accounts>Fetch New Datal>Exchange Account>Set to Fetch. Then go back one screen - the one where you selected the offending Exchange Account - and scroll to the bottom and make sure Fetch is set to 15 minutes.

This has worked for me over the last 36 hours with no recurrence of the duplicate sent items.

Interesting. My problem is different from yours a bit: When I send an email I only get one copy in Sent Items. Then I file it into a folder associated with that account. A duplicate then appears in sent items. I don't actually ever have the two in there at the same time the way you do in the photo.

For the past few days I have also been using Outlook for iOS as a secondary app for my Exchange Account and it works as it should without duplicates. Inconvenient as that workaround may be...

These issues only started with iOS 13.

new iPhone XR with everything up to date.

2 email accounts on office365. (Exchange).

duplicate emails in sent folder but only one actually sent as proven by checking outlook desktop, OWA, outlook iOS and simply asking the recipient.

open the duplicate sent and then go back to the sent folder and it disappears

synch issues with email-for example, delete several emails on iPhone and leave them in trash. Go to outloook desktop and those deleted emails show in desktop trash. Empty desktop trash and the emails stay in trash on iPhone. In some cases they won’t go away without deleting the email account on iPhone.

move email to a folder and it doesn’t synch across platforms.

Outlook iOS doesn’t have any of these issues although there are several others that make it less desirable to use.

So many issues, I almost forgot

inbox-read and delete an email and it reappears in the inbox. Delete the second one but there’s only one in trash. Apparently the second is just a “ghost”.

reply or forward an email and most of the original message is truncated.

Tested with iOS 13.2.3 - Duplicate sent items remain.

Deleted the Outlook.com account and configured new - Duplicate sent items remain.

No solution yet. Frustrating!

I recommend NOT to update to iOS 13 as my customers have all Outlook.com or MS Exchange Online Accounts.