When DelegateSentItemsStyle is set, the Mail is always stuck in Outbox

Question

When DelegateSentItemsStyle is set, the Mail is always stuck in Outbox

Aus der Au Dino 0

We saw online on TechNet, that it is possible to send a mail in the name of a shared Mailbox and we tried to save the mail in the sent items in the shared Mailbox, cause we don't need a copy in the primary Mailbox.
I attached an image from TechNet, where MS is explaining what constallation is needed. The red marked Window is our goal.

We configured it like that and it works basically. The only thing is, that the mail is showed as stuck in the outbox. We tried every possibility but nothing worked. At the end of the day, we belive that the info is wrong or something to get it right is missing...

We uses Exchange 2019 CU15 with Outlook 2016 and Outlook 365 with the newest Updates from MS.

For the moment we configured the Option in the blue marked Window. That is ok for the moment, but we don't need a copy in the primary Mailbox.

DelegateSentItemsStyle_Matrix

thx for inputs and ideas :)
kind regards, Dino

Anonymous

2025-03-24T07:52:25.76+00:00

Hi @Aus der Au Dino ,

If the issue has been resolved, please mark the helpful replies as answers, this will make answer searching in the forum easier and be beneficial to other community members as well. Thanks for your understanding.
Anonymous

2025-03-28T07:38:40.1233333+00:00

Hi @Aus der Au Dino ,

It's been a long time since I've heard from you, have you solved your problem yet? Did my previous reply help you？ If it was useful, you can mark it as an answer. Thank you for your understanding and support.
Anonymous

2025-04-02T08:40:04.02+00:00

Hi @Aus der Au Dino ,

Any updates so far? If you have solved your problem, could you share with us? Maybe it will help more people with similar problems. Don't forget to mark it as answer, this will be easy for other community members to find the useful one.

3 answers

Your answer

Anonymous

2025-03-24T07:52:25.76+00:00

Hi @Aus der Au Dino ,

If the issue has been resolved, please mark the helpful replies as answers, this will make answer searching in the forum easier and be beneficial to other community members as well. Thanks for your understanding.
Anonymous

2025-03-28T07:38:40.1233333+00:00

Hi @Aus der Au Dino ,

It's been a long time since I've heard from you, have you solved your problem yet? Did my previous reply help you？ If it was useful, you can mark it as an answer. Thank you for your understanding and support.
Anonymous

2025-04-02T08:40:04.02+00:00

Hi @Aus der Au Dino ,

Any updates so far? If you have solved your problem, could you share with us? Maybe it will help more people with similar problems. Don't forget to mark it as answer, this will be easy for other community members to find the useful one.

Answer 1

Hi @Aus der Au Dino,

Thank you for posting your question in the Microsoft Q&A forum.

According to your description, you want to implement saving a copy of an email only in the Sent Items of the shared mailbox.

Since you want to save a copy of the email in the shared mailbox and not in the primary mailbox, the DelegateSentItemsStyle registry value needs to be set to 1, the Mailbox's MessageCopyForSentAsEnabled parameter needs to be set to False, and Outlook must be configured to run in cache mode in order for this option to work. and Outlook must be configured to run in cached mode for this option to work.

Based on your description, I think you may have forgotten to configure Outlook to run in cached mode, you can change the profile to cached mode according to the following documentation. Email remains in Outbox if using DelegateSentItemsStyle - Outlook | Microsoft Learn

Below is my test procedure to successfully save a copy of an email only in the Sent Items of a shared mailbox.

close outlook after configuring it to run in cached mode.

User's image

Close Registry Editor after setting DelegateSentItemsStyle and MessageCopyForSentAsEnabled.

User's image

Open outlook and send an email from the shared mailbox. As you can see from the image below the email copy is only saved in the Sent Items of the shared mailbox.

User's image

If the answer is helpful, please click on “Accept answer” as it could help other members of the Microsoft Q&A community who have similar questions and are looking for solutions.

Thank you for your support and understanding.

Answer 2

Aus der Au Dino 0

Hi @Anonymous

Look at this ;) I'm the meaning, that it should work - otherwise the info on TechNet is wrong/uncomplete. So what do you think?

For your Info - We've had bad experiences with Cached-Mode. Not for technical reasons, but rather in the behavior of users with cache mode enabled. Since we disabled it, there have been no more problems. Either they're online (and everything's working perfectly) or they're not online (this state is also very understandable for the Users). This simply to complement the facts
DelegateSentItemsStyle_Info

Anonymous

2025-03-17T07:08:37.42+00:00
Hi Aus der Au Dino,

Thank you for your prompt response and clarification.

I think the information in TechNet is correct, you need to differentiate between ‘server only configuration’ or ‘both server + client registry configuration’ scenarios.

with a server-only configuration, there is no need to consider Outlook configured in online or cached Exchange mode, and you can use only the command line to achieve that a copy of your emails will be saved in both the primary and shared mailboxes.

When configured with both server + client registry, Outlook must be configured to run in cached mode for this option to work properly.

As you mentioned earlier that you want to save a copy of the email in the shared mailbox and not in the primary mailbox, then you need to configure it with both server-side and client-side registry, so Outlook needs to be configured to run in cached mode.

If the answer is helpful, please click on “Accept answer” as it could help other members of the Microsoft Q&A community who have similar questions and are looking for solutions.

Thank you for your support and understanding.

Answer 3

Aus der Au Dino 0

Hi @Anonymous

I accept the answer - but i cannot belive that i have to run Outlook in cache mode...

Ok, that was a joke :) unfortunately, I expected this to be so limited and semi-professional - Nothing new in the MS Cosmos.

we let it run with the server-side config, cause we don't want to use cache-mode.
But thx for your answers and help - It's nice that there are good supporters!

Anonymous

2025-03-19T01:28:05.4866667+00:00

Hi @Aus der Au Dino ,

Very happy to have been able to help you. If the issue has been resolved, please mark the helpful replies as answers, this will make answer searching in the forum easier and be beneficial to other community members as well. Thanks for your understanding.

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When DelegateSentItemsStyle is set, the Mail is always stuck in Outbox

3 answers

Your answer