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.

Update: This issue cleared up for me on its own. Cannot say a specific time but less than a day.
Hornblower409 16,075 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 5 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 16,075 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 5 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 16,075 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.
Brian J 0 Reputation points

2026-08-17T13:06:58+00:00

From Microsoft:
I understand how concerning it can be when changes made in Outlook do not appear to sync immediately.

In some cases, synchronization can become temporarily delayed or stuck on the server side, which may prevent Outlook from immediately receiving or updating the latest changes. As a result, updates such as calendar changes, email actions, or other mailbox modifications may take longer than expected to appear in the Outlook app, even though no error message is displayed.

Please let us know if the issue occurs again or if you notice any further synchronization delays.
Jim L 0 Reputation points

2026-10-01T22:05:41.0933333+00:00

I am having the same issue with emails not being marked as read or moved into another folder/label for my gmail. I am going on day 3 and what i am hearing is just wait it out? Is that the best advice?

2 answers

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.

Update: This issue cleared up for me on its own. Cannot say a specific time but less than a day.
Hornblower409 16,075 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 5 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 16,075 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 5 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 16,075 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.
Brian J 0 Reputation points

2026-08-17T13:06:58+00:00

From Microsoft:
I understand how concerning it can be when changes made in Outlook do not appear to sync immediately.

In some cases, synchronization can become temporarily delayed or stuck on the server side, which may prevent Outlook from immediately receiving or updating the latest changes. As a result, updates such as calendar changes, email actions, or other mailbox modifications may take longer than expected to appear in the Outlook app, even though no error message is displayed.

Please let us know if the issue occurs again or if you notice any further synchronization delays.
Jim L 0 Reputation points

2026-10-01T22:05:41.0933333+00:00

I am having the same issue with emails not being marked as read or moved into another folder/label for my gmail. I am going on day 3 and what i am hearing is just wait it out? Is that the best advice?

Answer 1

@Jim L said

I am going on day 3 and what i am hearing is just wait it out? Is that the best advice?

I wish I could give you something solid. But even though multiple reports started showing up in late August 2026, Microsoft has not published any Service Health notice or "Known Issue" doc (that I have seen) as of 2026-10-03.

Submit a Problem Report

Every Report moves this issue just a tiny bit higher on the Microsoft Fixit List. That's all any of us can do for now.

New Outlook for Windows In-App Problem Report

From the main menu: Help -> Feedback
{This should open the Help side panel}
Select "Report a problem"
Fill in the "Describe your problem ..." text box. (See below)
Can we contact you about this feedback -> Yes
Collect logs for feedback -> Yes
Click [Submit]

Copilot suggest this as a concise problem description that you can copy/paste into your Problem Report (feel free to improvise).

New Outlook for Windows: Gmail → Outlook sync works, but Outlook → Gmail sync intermittently fails. Message read/unread status, moves, deletions, and some calendar changes made in Outlook are not reflected in Gmail. No sync errors are displayed.

LMC 5 Reputation points

2026-10-02T13:29:54.8766667+00:00

I have reported it using the instructions you provided, thanks.

Answer 2

LMC 5

I have the same issue that it is syncing from Gmail to New Outlook i.e. all emails are arriving as expected. However actions taken on that email inconsistently sync back to Gmail. Each afternoon anything I have deleted from Outlook pings back into my Outlook inbox. Most suggestions seem to be a POP/IMAP issue but you can't check these settings in New Outlook. I checked what I could and my account appears to be added as IMAP as needed. For what it's worth Copilot says New Outlook should sync deletions, read/unread, and sent email, but doesn't sync labels, folders and archiving. The most consistently suggested solution I have found is to revert to Classic Outlook.

Hornblower409 16,075 Reputation points

2026-10-01T23:32:31.9833333+00:00

@LMC said

Copilot says New Outlook ... doesn't sync labels, folders and archiving

Not sure where your Copilot pulled that from, but that's not the case. I speak from personal experience. Plus many of the reports on this issue are along the lines of "it all used to work OK, but now it don't". Not that there is something that never worked.

Most suggestions seem to be a POP/IMAP issue but you can't check these settings in New Outlook

New Outlook for Windows doesn't talk directly to your GMail server. It only talks to the Microsoft Cloud servers which act as a middle-man. They are the ones that talk to Google.

If you added your GMail account the normal way, there are no settings in New Outlook that you can, or should, change.
https://support.microsoft.com/en-us/outlook/getstarted/add-a-gmail-account-to-outlook-for-windows
LMC 5 Reputation points

2026-10-02T13:23:30.5566667+00:00

That's interesting thank you. I totally agree this is a new issue so the information doesn't make sense. I have used the new outlook for almost a year without issue, then this started several weeks ago. I do have issues with the labels etc. syncing so thought that might be helpful to know. I deleted and added the account a few times but the problem persists. I spent a long time trying to get everything set back up in Classic Outlook but it seems that the google calendar function is not compatible with Classic Outlook, so email works, but calendar not functional. It goes on...
Hornblower409 16,075 Reputation points

2026-10-02T14:02:29.6733333+00:00

@LMC said

Google calendar function is not compatible with Classic Outlook, so email works, but calendar not

A Google account in Classic Outlook is pure IMAP. Email only. It can store Calendar and Contacts for the account but they are local ("This Computer Only") and do not sync with the Google account.

You can get a Read Only Google Calendar via Subscribe
https://support.microsoft.com/en-us/outlook/calendar/see-your-google-calendar-in-outlook

But for a full Calendar/Contact sync you have to use a third party product.
LMC 5 Reputation points

2026-10-02T14:17:46.54+00:00

That's really helpful, thank you. I tried a 3rd party product but having mixed results. Was fine yesterday, all disappeared again today. I've reported as you suggested. Will pass on any responses.