Outlook 2021, win 10... emails are not being recived

Question

Outlook 2021, win 10... emails are not being recived

Park Avenue 0

A short while back, I had 2021 installed and working fine. Then I tried to add in Linux Mint to test some things. Somewhere along the way, I deleted the Mint stuff (rather complex) and things got really messed up. One of my hard drives had all of the files removed and my Windows 10 installation got messed up. I ended up reformatting the SSD that 10 was installed in, re-installed a fresh copy, registered the OS and I thought everything would be fine.

Installed Outlook 2021, added in my multiple email accounts. When I do a send/receive, new emails are not showing up.

I did a test message send from my primary account, sent a copy to all of the other accounts, and things were not working. I would get 1 message in, notifications showed the new message. I would click on the notification, it would load the email. Yet when I went to find it, it just wasnt there.

The new message would show up in the inbox... I would close outlook, and then re-open it... and the new message was gone.

This problem is happening to every email account I have set up. I went in and did a check on the data files, they were taking less than 1 gb of space, so there was lots of room... Most of the email accounts are setup using Microsoft Exchange.

How can I get all of these emaills back, and get new messages?

Thanks in advance. Gary :)

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Answer 1

Ana Le 2,220 Independent Advisor

Hi,

Based on your description, Outlook is detecting new messages because you receive the notification and can briefly open the email. However, the fact that the message disappears after restarting Outlook suggests the issue may be related to the local Outlook profile, cached data, or synchronization rather than mail delivery itself.

To help narrow down the cause, could you check the following?

1/ Are the missing messages still visible when you access the same mailbox using Outlook on the web?

If they are present on the web but disappear only in the Outlook desktop app, the issue is likely with the local Outlook profile or cache.
If they are also missing on the web, the messages may be getting moved or deleted by a server-side rule or another client.

2/ Does the issue occur if you start Outlook in Safe Mode?

Press Windows + R, type: outlook.exe /safe

If the problem disappears in Safe Mode, an Outlook add-in may be causing the behavior.

3/ Since Windows and Office were reinstalled, try creating a new Outlook profile:

Control Panel > Mail > Show Profiles > Add

Configure your Exchange account in the new profile and set it as the default. This will generate a new offline cache (OST) and rule out profile corruption.

4/ If you’re using Cached Exchange Mode, temporarily disable it, restart Outlook, and test again. If the issue no longer occurs in Online Mode, the local OST cache is likely involved.

Please also let me know:

Which version and build of Outlook 2021 are you using? File > Office Account > About Outlook
Are all affected accounts Exchange accounts, or do POP/IMAP accounts show the same behavior?
Are there any Inbox rules or Quick Steps configured?

Park Avenue 0 Reputation points

2026-07-24T14:44:43.46+00:00

First of all, thanks kindly for the fast and in depth response. I am in win 10 now, loaded one of my main accounts using the web via hotmail.com. I have a few new messages showing up there, I have not yet run outlook classic on the desktop for fear of losing them. I have around 10 emails with hotmail or live dot com, and I have only checked the one main account that I use.

Running outlook in safe mode. The web messages are not showing in the desktop, but they do remain on the website. I started exploring the "rules" and found a couple that were weird. Seems there are different rules for each email address I have, and I think the best bet would be for me to nuke all of the rules for all of the accounts. Doesnt seem to be an easy way to do that...

Microsoft® Outlook® LTSC MSO (Version 2408 Build 16.0.17928.20114) 64-bit

Product ID: 00470-90000-00000-AA435

Just a FYI, the new messages on the web have disappeared....
Park Avenue 0 Reputation points

2026-07-24T14:47:39.9566667+00:00

First of all, thanks kindly for the fast and in depth response. I am in win 10 now, loaded one of my main accounts using the web via hotmail.com. I have a few new messages showing up there, I have not yet run outlook classic on the desktop for fear of losing them. I have around 10 emails with hotmail or live dot com, and I have only checked the one main account that I use.

Running outlook in safe mode. The web messages are not showing in the desktop, but they do remain on the website. I started exploring the "rules" and found a couple that were weird. Seems there are different rules for each email address I have, and I think the best bet would be for me to nuke all of the rules for all of the accounts. Doesnt seem to be an easy way to do that...

Microsoft® Outlook® LTSC MSO (Version 2408 Build 16.0.17928.20114) 64-bit

Product ID: 00470-90000-00000-AA435

Just a FYI, the new messages on the web have disappeared....
Hornblower409 12,375 Reputation points

2026-07-25T04:19:37.1266667+00:00
@Park Avenue said

nuke all of the rules for all of the accounts. Doesnt seem to be an easy way to do that...

Make a backup of any existing Rules from all accounts:

File -> Manage Rules & Alerts

On the "Email Rules" tab -> [Options]

On the Options dialog -> [Export Rules]

Clean all Rules:

Close Outlook completely.

Press Win + R on your keyboard to open the Windows Run dialog box.

Type outlook.exe /cleanrules into the box and press Enter.

Note - If you have multiple email accounts or manage shared mailboxes, this will delete the Rules from all of them.
Park Avenue 0 Reputation points

2026-07-25T12:25:35.3566667+00:00

When I first started checking rules, I found one account entry where the rule was named "Always"... when I looked at that rule, I found no entry in the first part. Not familiar with an email from "Always". It ended up that the only entry in the sections was to "delete" which is where I suspect my main problem came from. I went through all the accounts, several had no rules at all. The ones that did have rules defined, I deleted them all.

I will do another email test, sending a test message from my primary account to all of the other email accounts and see if things are being processed, and to see if things get deleted after I close outlook.

I am not a fond fan of exchange server, and I would like to change everything back to POP or IMAPI. 95% of my emails are hotmail or live dot com. Can this be done without Microsoft and Outlook having a hissie fit? :)

Gary
Hornblower409 12,375 Reputation points

2026-07-25T14:11:23.63+00:00

@Park Avenue said

"Always"... when I looked at that rule, I found no entry in the first part.

Is the Condition (first part) in the Rule Description "Apply this rule after the message arrives"? If so, then it's an "All Mail" rule.

When creating a new Rule, if you don't select anything for the first step (Condition) and just hit [Next] you get a Rule that runs on all incoming mail.
Park Avenue 0 Reputation points

2026-07-25T14:25:47.6566667+00:00

Interesting... I have sometimes "missed" the first part, and it wouldn't let me continues. shrug ... Anyway it seems like the issues were all around the "rules" side of things. I can now get email in to all of the other accounts, I think there are around 9 of them.

I do appreciate all of the help in getting this sorted out. Doesn't look like I will ever be able to retrieve all of the missing emails.... which is why I want to go back to POP or IMAPI. Is this going to be an issue?

Thanks again...

Gary
Hornblower409 12,375 Reputation points

2026-07-25T14:35:26.99+00:00

@Park Avenue said

want to go back to POP or IMAPI

Before going on to that point, if you would please - You did a clean install of Outlook 2021? If so, there should not have been any Rules defined. Do you have any idea where the Rules came from? Specifically an "All Mail" Rule that does nothing but Delete?
Park Avenue 0 Reputation points

2026-07-26T14:37:16.4033333+00:00

I had 2021 installed on Win10 at one point, many rules created because I got tired of all of the casino ads and free spins... then my Win10 SSD drive had a hiccup and I ended up formatting it (took a backup first) and re-installing 10. I can only presume that Exchange server kept a copy of the rules and put them in place when I re-installed Outlook.
Park Avenue 0 Reputation points

2026-07-26T14:39:36.4033333+00:00

I can only presume that Exchange had a copy of the rules from my previous install, and put them in place when I installed 2021 again. :)
Hornblower409 12,375 Reputation points

2026-07-26T14:47:52.9166667+00:00

@Park Avenue said

95% of my emails are hotmail or live dot com ... Most of the email accounts are setup using Microsoft Exchange ... I want to go back to POP or IMAPI.

You can certainly configure a Microsoft Hosted email account as IMAP.
https://support.microsoft.com/en-us/outlook/pop-imap-and-smtp-settings-for-outlook-com

On the Classic Outlook Add an account screen use the Advanced options, "Let me set up my account manually" choices.

Most people stay with the standard Exchange connection because it offers full control/sync of the account (Calendar, Contacts, Rules, etc.)
Ana Le 2,220 Reputation points Independent Advisor

2026-07-27T07:33:22.99+00:00

Hi,

Thank you for the update, and I'm glad you were able to identify the cause.

It does appear that the issue was caused by an Inbox rule that applied to all incoming messages and deleted them. Since Outlook.com/Exchange stores rules on the mailbox rather than on the local PC, those rules can be synchronized back to Outlook even after Windows or Office is reinstalled, which explains why they reappeared after your clean installation.

I'd also like to thank Hornblower409 for the valuable troubleshooting suggestions throughout this discussion. The guidance on reviewing the Inbox rules helped identify the root cause, and the clarification about using IMAP versus Exchange also answered your final question.

As for the previously deleted messages, unfortunately, if they are no longer available in the Deleted Items folder or the Recover deleted items option, Outlook won't be able to restore them.

I'm pleased to hear that new messages are now arriving correctly across all of your accounts. If you run into any other issues, please don't hesitate to let me and other users of community know.
Park Avenue 0 Reputation points

2026-07-27T12:20:50.5466667+00:00

Ah... deleted items folder... recovered the important ones, thanks kindly for pointing me in that direction.

Yes, everything seems to be working fine. Will ponder on the IMAPI changes for a bit, see what happens. And I still wonder on how "that" rule made it into rules... it never should have happened.