Customized Oversharing Dialog not working for Exchange DLP

Question

Customized Oversharing Dialog not working for Exchange DLP

Mansha Irfan 145

Hi,

When I'm enabling policy tip as a dialog for custom content. This is not working (not getting customized options as shown in picture below). I'm testing this option on new outlook. Can anyone guide what is wrong here?

User's image

and this is my JSON file

{

"LocalizationData": [

{

"Language": "en-us",

"Title": "Add a title",

"Body": "Add the body",

"Options": [

"I have a business justification",

"This message doesn't contain sensitive information",

"Business justification"

]

}

],

"HasFreeTextOption": "true",

"DefaultLanguage": "en-us"

}

User's image

Answer accepted by question author

0 additional answers

Your answer

Answer 1

Pratyush Vashistha 5,045 Microsoft External Staff Moderator

Hey Mansha! It sounds like you’re having some trouble with the customized oversharing dialog not working in the new Outlook client for your DLP policy. From what you’ve provided and the relevant documentation, here’s what you should know:

Currently, the new Outlook client doesn't support customized oversharing dialogs; it only utilizes the default out-of-the-box dialog. This means that even though you have set up your JSON file correctly, it won't display the custom options you are expecting.

Limited Support: Customized oversharing dialogs are not supported in the new Outlook for Windows or Outlook Web.
Default Behavior: In the new Outlook client, the dialog defaults to the standard content rather than your customized options.

Suggested Steps:

Verify Outlook Version: Make sure that you are indeed using the new Outlook client, which has these limitations.
Check Licensing: Ensure that you have the appropriate Microsoft 365 E5 subscription, as this is required for DLP policy features.
Review JSON Configuration: Although your JSON looks correctly formatted, it unfortunately won't affect the dialog display due to the current limitations.

Unfortunately, the behavior you're seeing is by design, so there isn't a specific configuration that can be changed to resolve this issue within the new Outlook client. If customizing the dialog is critical for your use case, consider using an older version of Outlook or keeping an eye on future updates, as Microsoft may change this functionality.

Reference Links:

Hope this helps clarify things for you! If you have more questions or need further assistance, feel free to ask!

Please "Accept as Answer" or click 'Thumbs Up YES' if the answer provided is useful, so that you can help others in the community looking for remediation for similar issues.

Thanks

Pratyush

Mansha Irfan 145 Reputation points

2025-12-04T04:37:23.4633333+00:00

Thanks for your answer. I did test on classic outlook too, it's not working

No policy tips, no override option, no customized pop up

My classic outlook version:
Pratyush Vashistha 5,045 Reputation points Microsoft External Staff Moderator

2025-12-04T04:50:55.0333333+00:00
Thanks for confirming that and sharing the screenshot, it’s helpful to see exactly what you’re experiencing.

Since the custom oversharing dialog isn’t appearing even in classic Outlook, and you’re seeing only the basic warning without any policy tip or override option, we need to dig a little deeper. The fact that you’re on version 2510 (Click-to-Run) suggests you’re actually running the new Outlook, not the classic one, Microsoft has been rolling out the new client by default, and sometimes the interface still looks familiar but it’s not the legacy version.

So, here’s what I’d like to clarify:

Is your DLP policy configured to trigger on the exact content type and recipient condition you’re testing? For example, does the file you’re attaching match the sensitive info type defined in the policy?

Are you testing with an external recipient (as shown in your screenshot), and is your policy set to block or warn on external sharing?

Have you waited at least 24 hours after publishing the policy? Sometimes policies take time to propagate fully across all clients.

Also, just to be thorough are you using a Microsoft 365 E5 license? That’s required for DLP policy tips to function at all.

Let me know those details, and I’ll help you narrow down whether this is a configuration issue, a licensing gap, or a client misidentification, we’ll get this sorted.
Mansha Irfan 145 Reputation points

2025-12-04T05:17:15.9766667+00:00

The answer to all above question is YES. Also, I have E5 license. Sharing SS of configured policy. The same excel file is showing policy tips for new outlook.
Pratyush Vashistha 5,045 Reputation points Microsoft External Staff Moderator

2025-12-04T05:39:17.7866667+00:00

Thanks for confirming all the details and for sharing the policy screenshot. It’s clear you’ve set this up correctly, with the right conditions (Malaysian phone numbers and ID cards) and actions (blocking external sharing), and you’re on E5, which is required.

The fact that the same Excel file triggers a policy tip in the new Outlook but not in what you thought was classic Outlook is actually the key clue here. Since you’re seeing the policy tip in the new client, it means your DLP policy is working as intended but only in the environment where Microsoft currently supports it: the new Outlook client.

What’s likely happening is that you’re not actually using “classic Outlook” even if the interface looks familiar, you might still be on the new Outlook client. Microsoft has been gradually replacing classic Outlook, and sometimes the transition isn’t obvious. The version number you shared (2510, Build 19328.20244 Click-to-Run) is from the new Outlook, not the legacy one.

So, here’s the bottom line:

Your custom oversharing dialog won’t appear because custom dialogs are not supported in any Outlook client right now, not even in classic Outlook. Microsoft’s documentation confirms this: only the default system dialog shows up, regardless of JSON configuration.

The policy tip you’re seeing in the new Outlook is the standard behavior and it’s working correctly. If you need to customize the message or add override options, unfortunately, that’s not available today. You can either rely on the default warning or monitor future updates from Microsoft for potential support.

If this anyhow answers your query, do click Accept Answer and Yes for was this answer helpful. And, if you have any further query do let us know.

Thanks

Pratyush

Share via

Customized Oversharing Dialog not working for Exchange DLP

Suggested Steps:

Reference Links:

0 additional answers

Your answer