fix removing Unknown Users (deleted account) in group chats.

hi chanwei21​ 

You're facing two fairly common and frustrating issues in Microsoft Teams related to managing group chats in an organizational context. Let's break them down and walk through possible solutions or workarounds.

1.Can't remove “Unknown User” (Deleted account) from group chat

Error Message: “We couldn’t remove one or more people from the chat”

Cause:

• The "Unknown User" typically represents a deleted user account from Azure AD.
• Even if you're an owner, Teams may not allow you to remove deleted accounts from chats due to permission constraints, or because Teams retains chat history with all original participants for audit and compliance reasons.

Workarounds:

1. Use PowerShell to Clean Up Deleted Users:
   Microsoft doesn't currently allow direct removal of deleted users from chats, but you can check the Azure AD and Teams settings using PowerShell.

You can try:

Get-TeamUser -GroupId <GroupId>

But for chats (not teams), there's currently no supported PowerShell command to forcibly remove a user from a group chat.

1. Recreate the Group Chat (Best Practical Solution):
• Start a new group chat with only active members.
• Use the “Name this group chat” feature to maintain clarity.
• Inform team members of the transition and pin the new chat.
2. Feedback to Microsoft:
• This is a known limitation and has been requested by many admins.
• You can upvote or submit a feature request here: https://feedbackportal.microsoft.com

2.User who left still shows up in the group chat list and can't be removed

Cause:

• The user may have left voluntarily, but Teams retains their presence in the chat for historical reference.
• They still show up in the "People" list, even if they no longer receive messages.
• Removing them as owner also fails with the same permission error.

Workarounds:

1. Chat Retention Policy:
   Check if your Teams messaging policies or retention policies prevent full removal. Talk to your IT admin to:
• Review your Teams retention policy in Microsoft 365 Compliance Center.
• Ensure no policy is locking deleted or exited users in the chat.
2. Try Removing from Microsoft Teams Web App:
   Sometimes the web version behaves slightly differently. Try removing the user from:
• https://teams.microsoft.com
• Clear cache or use InPrivate/Incognito mode.
3. Same Solution: Create a New Chat
   As with Problem #1, the most straightforward path to regaining control is to start a new chat thread and manage members cleanly.

Regarding the “20 participants read receipt limit”

Unfortunately, this is a hard limit set by Microsoft:

Teams chat read receipts are only shown for up to 20 participants in a group chat.

Submit feedback directly to Microsoft using:

• Teams client > Help (?) > Give Feedback
• Or Microsoft Teams Feedback Portal