Unable to remove autosuggest email from Outlook

Based on recent reports from multiple users, this behavior appears to be related to a change in newer Outlook for Microsoft 365 builds, rather than a local cache issue or client‑specific misconfiguration.

Microsoft has announced the retirement of the Contact Masking feature, which allowed users to hide suggested recipients by clicking the“X” next to a name in the To/Cc/Bcc suggestion list. This change is rolling out across Outlook Desktop, Web, and Mobile and reaches end of support on March 31, 2026. As part of this retirement, previously hidden suggestions may reappear, and the“X” delete icon may no longer be available or behave consistently in newer builds (including Version 2604, Build 19929.20086).

As a result, AutoSuggest entries in classic Outlook may no longer be reliably removable using the usual deletion methods. Entries that appear to be removed can reappear, which may look like looping or inconsistent AutoComplete behavior.

A related discussion Outlook 365 Classic Autocomplete gone strange describes similar, though not identical, symptoms. While that thread doesn’t describe the exact same looping behavior, it reinforces that AutoComplete removal and persistence has become inconsistent in recent versions of classic Outlook, which may explain why the usual deletion methods no longer work reliably.

This functionality was simply removed in the latest release of Outlook.

I created a post in the Microsoft Feedback Forum to restore this functionality.  Please help by upvoting it!

https://feedbackportal.microsoft.com/feedback/idea/97490d3b-7d45-f111-9a91-000d3a05c4f5

Hi @Rahuleo 

Starting with Outlook for Microsoft 365 Version 2202 (Build 14931.20604), when connected to an Exchange Online mailbox, recipient suggestions in the To/CC/BCC fields are powered in part by Microsoft Search. 

When you delete entries from the AutoSuggest list, they are removed from the AutoComplete cache. However, suggestions may reappear if they are reintroduced from other sources, such as Microsoft Search signals or other Outlook clients connected to the same mailbox. 

If contact discovery is enabled, Microsoft Search may use previously learned communication data (for example, frequently contacted recipients) to suggest addresses again. You may try going to My Account - Settings & Privacy > Manage contact suggestions and discovery to clear discovered contacts data and turn contact discovery off, but Microsoft does not document this as a guaranteed or supported fix for Outlook desktop AutoComplete issues.

If entries continue to reappear, it may be due to sync conflicts or cache rehydration. Here are troubleshooting steps you can try: 

1.Roaming AutoComplete cache 

-Sign out of Outlook completely, close the app, then reopen and test.  

-If the issue persists, remove entries in Outlook Web (OWA):  

-Go to New message > Start typing the name > click X on the suggestion. 

(This affects OWA-specific suggestions and can help reduce reintroduction.)

2.Check all Outlook clients  

If you use Desktop, Mobile, and Web, one of them may still hold the old cache and reintroduce entries. Remove suggestions across all clients.  

3.Temporarily disable add-ins to check for interference 

-Close Outlook completely.     

-Press Win + R, type: outlook.exe /safe > Press Enter.     

If Outlook opens normally in Safe Mode, the issue is likely caused by an add-in.    

-Go to File > Options > Add-ins > COM Add-ins > Go > Disable all add-ins, then re-enable them one by one to identify the problematic add-in.    

Reference: Open Outlook in safe mode - Microsoft Support.    

4.Create a new Outlook profile:   

Control Panel > Mail > Show Profiles > Add > create a new profile > add your account > set as default > restart Outlook.    

Reference: Create an Outlook profile - Microsoft Support.  

I hope this helps. 

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