Recipient.add problem after latest updates

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Recipient.add problem after latest updates

Paul Martin 5

We use OLE to communicate with Outlook in our software. We have had reports from multiple customers that their system is no longer working properly when trying to send emails. We have tracked this down to recipient.resolve method returning false following the recipient.add

Issues reported since update to the updates from April 21st. 16.0.19929.200.90 (2604 apps for business)

The code has worked without issue for years and is a fundamental part of sending a batch of emails so that the customer does not have to manually send each email.

if we ignore the .resolve failure and use .send on the mail item, it will fail but using .display and then pressing send on the displayed email works fine. I would guess that it is the .add that is not reporting a failure.

has anyone else found this and better yet, come up with a solution for it?

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Answer 1

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Answer 2

Gabriel-N 16,475 Microsoft External Staff Moderator

Hello Paul Martin

Recently, this forum has received reports of issues occurring in Office Version 2604 (Build 19929.20090) on the Current Channel.

If your customer is using this version, as also AI mentioned, please consider rolling back to Version 2603 to check whether the issue is resolved and whether the script works as expected. For reference, you can review the discussion here: Office 365 Update version 2604

Additionally, if your customers are on the Monthly Enterprise Channel and are experiencing the same issue, you may consider switching temporarily to the Current Channel (Version 2603) to test. If this resolves the problem, I recommend keeping Office on Version 2603 and waiting for a newer Office build before testing again.

I also suggest submitting feedback by opening a support ticket through the Microsoft 365 Admin Center, or directly feedback from Outlook via Help > Feedback, so this issue can be investigated further.

I hope this information is helpful. Please let me know the outcome after rolling back so I can continue to support you.

Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

Hornblower409 8,190 Reputation points

2026-04-29T05:12:03.9866667+00:00

@Gabriel-N said

received reports of issues occurring in Office Version 2604 (Build 19929.20090) on the Current Channel.

FWIW - I have been working this same issue about Outlook recipient.resolve method returning false even when given a valid user name on Reddit:

https://www.reddit.com/r/vba/comments/1sxw868/outlook_recipientadd_problems_after_latest_update/

But I am on 2604 and could not reproduce the problem.

One user reported that changing from recipient.resolve to .Recipients.ResolveAll fixed the issue. But I don't have any other confirmations.
Gabriel-N 16,475 Reputation points Microsoft External Staff Moderator

2026-04-29T07:30:09.38+00:00

Hi Hornblower409, thank you for your information, it’s really helpful.

And Paul Martin, is there any update from your side? Please take a look at Hornblower’s suggestion, as it also provides another approach to this issue.

If you still have any further concerns, please feel free to let us know.
Hornblower409 8,190 Reputation points

2026-04-29T23:50:04.74+00:00

Just FYI - Might be a similar problem being reported in the Spiceworks forum.

Description is that a third party product was failing to send with Outlook 2604 when the profile had (what I assume were) multiple Exchange accounts. Using only one account, or rolling back to 2603 fixed the problem.

I don't have any problems with 2604 and don't have access to multiple Exchange accounts so I can't test.
Hornblower409 8,190 Reputation points

2026-04-30T03:10:03.32+00:00

Report from another Reddit user:

In our case it was a car dealership software using MAPI to send out emails through Outlook which stopped working for most users. I can confirm creating a new Outlook profile with 1 x Exchange account worked perfect. An Outlook with multiple Exchange accounts failed every time.
Paul Martin 5 Reputation points

2026-04-30T10:57:50.52+00:00

Thank you all.

resolve.all did not work for us.

we are currently helping people get setup with SMTP accounts which to be honest is a better setup for bulk emailing anyway.

i shall try setting up a profile with one exchange account
Hornblower409 8,190 Reputation points

2026-04-30T13:59:08.39+00:00

@Paul Martin said

We use OLE to communicate with Outlook
resolve.all did not work for us

But .Display and manual Send does work. Weird. I would have thought that manual Send was calling Resolve.All . Something to do with it being done externally and not from Outlook VBA? Sorry. I can't test.
Gabe Bratton 776 Reputation points Microsoft Employee Moderator

2026-05-01T20:30:20.26+00:00

@Paul Martin I suspect the issue you are seeing might related to this other post, https://learn.microsoft.com/en-us/answers/questions/5874363/office-current-channel-build-19929-20090-breaks-th. I was able to repro that issue, and I escalated it to the Outlook Team. The Outlook Team is working on a change that will address that issue. It should be in production early next week. I can post back when I know for sure and can check if it helps mitigate your issue too.

Answer 3

The behavior matches known regressions in recent Outlook for Microsoft 365 builds where programmatic/MAPI‑based or add‑in–based sending starts failing after an Office update, while manual sending from a displayed item still works. Similar issues have been seen after specific builds and were resolved either by updating to a fixed build or reverting to a previous one.

Given that the issue started immediately after updating to a specific Office build and the same code worked for years, the supported workarounds from similar Outlook issues are:

Update Outlook to a fixed build (preferred)
Check whether a newer build than 16.0.19929.20090 is available for the 2604 channel and install it. Many Outlook send‑path regressions are marked as STATUS: FIXED in later builds and resolved simply by updating. From Outlook Desktop:
- File → Office Account → Update Options → Update Now.
Temporarily revert Outlook to a prior working build
If the current channel build is the cause and no fixed build is yet available on that channel, revert to a previous version known to work. For Current Channel, a documented example of reverting is:
1. Open Command Prompt as Administrator.
2. Run:
```
      cd %programfiles%\Common Files\Microsoft Shared\ClickToRun
      officec2rclient.exe /update user updatetoversion=16.0.17425.20236
```
For other channels (e.g., Monthly Enterprise), choose a build prior to the regression using the Office update history and revert similarly. This is the same pattern used in the documented workaround for Outlook send issues after specific builds.
Check for add‑ins or On‑Send logic interfering
Some recent issues were triggered by web add‑ins with On‑Send actions. As a diagnostic step:
- Disable or uninstall any Outlook add‑ins that hook into sending (especially On‑Send).
- Retry the OLE automation after add‑ins are removed or after the add‑ins refresh window (30 minutes to 4 hours) has passed.
Use Outlook on the web or New Outlook as a temporary workaround
While waiting for a fixed build or after reverting, affected users can send the same messages via Outlook on the web or the New Outlook client, which do not use the same desktop MAPI/OLE path.

Because the code works when the user manually sends after .Display, and the regression is tied to a specific build, the practical resolution is to move affected clients off the problematic build (either forward to a fixed build or back to a known‑good build) and verify that the .Recipients.Add/.Resolve/.Send sequence succeeds again.

References:

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Recipient.add problem after latest updates

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