New Outlook for Windows: Gmail changes intermittently fail to sync back to Google

Question

New Outlook for Windows: Gmail changes intermittently fail to sync back to Google

Brian J 0

I'm experiencing an intermittent synchronization issue between New Outlook for Windows and Gmail where Google → Outlook synchronization works, but changes made in Outlook sometimes fail to sync back to Google.

Environment

New Outlook for Windows: v1.2026.720.100
Gmail account connected directly to New Outlook
Issue reproduced with two separate Gmail accounts

What consistently works

New Gmail messages appear in Outlook
Emails sent from Outlook through Gmail send successfully
Google Calendar events appear in Outlook

What intermittently fails to sync back to Google

Deleting an email in Outlook → email remains in Gmail
Moving an email to another folder in Outlook → move isn't reflected in Gmail
Marking an email as read in Outlook → email remains unread in Gmail
Creating a Google Calendar event in Outlook → event sometimes doesn't appear in Google Calendar

For example, I can reproduce the email issue by:

Receive a Gmail message in New Outlook.
Mark it as read, move it, or delete it in Outlook.
Check Gmail on the web or mobile app.
The change made in Outlook is not reflected in Gmail, even after waiting for synchronization.

There are no sync errors, warnings, or authentication prompts in New Outlook.

Troubleshooting already attempted

Removed and re-added the Gmail account multiple times
Revoked Microsoft's access from my Google Account and reauthorized it
Confirmed Microsoft has Gmail and Google Calendar permissions
Verified calendar events are being created on the correct Gmail calendar
Tested a second Gmail account and reproduced the same behavior

Interestingly, the problem resolved itself for several days without any configuration changes, and two-way synchronization worked normally. It has now returned.

Because the same behavior occurs with two Gmail accounts and temporarily resolved on its own, it appears the issue may be with the synchronization between New Outlook and Google rather than an individual Gmail account.

How can I troubleshoot or resolve New Outlook intermittently failing to sync email and calendar state changes back to Google?

Alex Onda 0 Reputation points

2026-08-13T22:03:41.61+00:00

Gmail issues removed. My bad.
Jamie F 0 Reputation points

2026-08-14T12:45:15.8533333+00:00

Having the exact same issues. I use multiple devices (desktop, laptop, phone) to access my email and this issue is troublesome. Also, "read" emails in Outlook switch to "unread" a day or so later.
JimmyG 0 Reputation points

2026-08-14T13:16:43.89+00:00

I am having same issue.

Started between 8/13/26 and 8/14/26

From New Outlook client;

marking 'read' not syncing to gmail
'delete' not deleting in gmail
Hornblower409 12,510 Reputation points

2026-08-14T14:08:50.6533333+00:00

@Alex Onda and @JimmyG

Unless you have exactly the same problem as the original poster, you might be better served by starting a new thread using the "Ask a question" button at the top of this page to create a new Question and include the details for your specific problem and Outlook Client(s). This provides much higher visibility to your issue than commenting on an existing post.
MBDR09 0 Reputation points

2026-08-17T03:47:03.7033333+00:00

I am seeing exactly the same behavior. Additionally across three different Outlook clients, Windows, Tablet and Phone outlook shows the updates made on Outlook clients but the changes are not reflected in Gmail.
Hornblower409 12,510 Reputation points

2026-08-17T03:58:42.22+00:00
To: All

At this point all I can suggest is:

In App Support - New Outlook for Windows

From the main menu: Help -> ? Help

{This should open the Help side panel}

Search Help -> {Your problem} and press Enter

Still need help? [Yes]

If you get "We're here to help": Tell us your problem -> {Your problem, again} [Get Help]

[Sign In] {Use any Outlook/Microsoft account}

Choose a support option -> Chat with a support agent in your web browser

If you get anything useful from Microsoft Support, please report back for the rest of us.
MBDR09 0 Reputation points

2026-08-17T05:23:34.6133333+00:00

Response from Microsoft:

After reviewing the details you've provided, this does not appear to be an issue with Outlook itself. Outlook is successfully connecting to and syncing with your Gmail account, as new emails are received correctly, emails sent from Outlook are delivered successfully, Google Calendar events appear in Outlook, and Outlook syncs properly across all your devices.

As a result they suggest contacting Google for support to resolve the issue.
Hornblower409 12,510 Reputation points

2026-08-17T05:48:10.22+00:00
@MBDR09 said

[Microsoft Support] suggest contacting Google for support to resolve the issue.

I wish I could reproduce so I could debug. But just did some testing with my GMail in New Outlook for Windows and all is good for me.

Outlook Version: 1.2026.720.100, Client Version: 20260807011.11

Specifically tested:

Deleting an email in Outlook

Moving an email to another folder in Outlook

Marking an email as read in Outlook

So I don't think it's purely an Outlook client issue. Not sure what to suggest.

Your answer

Alex Onda 0 Reputation points

2026-08-13T22:03:41.61+00:00

Gmail issues removed. My bad.
Jamie F 0 Reputation points

2026-08-14T12:45:15.8533333+00:00

Having the exact same issues. I use multiple devices (desktop, laptop, phone) to access my email and this issue is troublesome. Also, "read" emails in Outlook switch to "unread" a day or so later.
JimmyG 0 Reputation points

2026-08-14T13:16:43.89+00:00

I am having same issue.

Started between 8/13/26 and 8/14/26

From New Outlook client;

marking 'read' not syncing to gmail
'delete' not deleting in gmail
Hornblower409 12,510 Reputation points

2026-08-14T14:08:50.6533333+00:00

@Alex Onda and @JimmyG

Unless you have exactly the same problem as the original poster, you might be better served by starting a new thread using the "Ask a question" button at the top of this page to create a new Question and include the details for your specific problem and Outlook Client(s). This provides much higher visibility to your issue than commenting on an existing post.
MBDR09 0 Reputation points

2026-08-17T03:47:03.7033333+00:00

I am seeing exactly the same behavior. Additionally across three different Outlook clients, Windows, Tablet and Phone outlook shows the updates made on Outlook clients but the changes are not reflected in Gmail.
Hornblower409 12,510 Reputation points

2026-08-17T03:58:42.22+00:00

To: All

At this point all I can suggest is:

In App Support - New Outlook for Windows

From the main menu: Help -> ? Help

{This should open the Help side panel}

Search Help -> {Your problem} and press Enter

Still need help? [Yes]

If you get "We're here to help": Tell us your problem -> {Your problem, again} [Get Help]

[Sign In] {Use any Outlook/Microsoft account}

Choose a support option -> Chat with a support agent in your web browser

If you get anything useful from Microsoft Support, please report back for the rest of us.
MBDR09 0 Reputation points

2026-08-17T05:23:34.6133333+00:00

Response from Microsoft:

After reviewing the details you've provided, this does not appear to be an issue with Outlook itself. Outlook is successfully connecting to and syncing with your Gmail account, as new emails are received correctly, emails sent from Outlook are delivered successfully, Google Calendar events appear in Outlook, and Outlook syncs properly across all your devices.

As a result they suggest contacting Google for support to resolve the issue.
Hornblower409 12,510 Reputation points

2026-08-17T05:48:10.22+00:00

@MBDR09 said

[Microsoft Support] suggest contacting Google for support to resolve the issue.

I wish I could reproduce so I could debug. But just did some testing with my GMail in New Outlook for Windows and all is good for me.

Outlook Version: 1.2026.720.100, Client Version: 20260807011.11

Specifically tested:

Deleting an email in Outlook

Moving an email to another folder in Outlook

Marking an email as read in Outlook

So I don't think it's purely an Outlook client issue. Not sure what to suggest.