To completely remove the old Workspace from your Slack app on Windows 11, follow these steps: Method 1: Use Slack’s Built-in Option (If Available)

1. Open Slack.
2. Look at the left sidebar where the workspace logos are displayed.
3. Right-click (or Ctrl + Click) on the workspace logo.
4. If "Remove Workspace" appears, select it. If that doesn’t work, proceed to the manual methods below.

Method 2: Clear Slack's App Data Since Slack stores some settings locally, clearing the cache and local files can remove the lingering workspace.

1. Close Slack completely
   • Right-click the Slack icon in the system tray (bottom-right corner) and select Quit Slack.
2. Delete Slack’s cache and storage files
   • Press Win + R, type the following, and hit Enter: %appdata%\Slack
   • Delete the folders named:
     • Cache
     • Code Cache
     • Local Storage
     • Session Storage
3. Delete Slack's settings
   • In the same Slack folder, delete storage and workspace.json if available.
4. Restart Slack and check if the workspace is gone.

Method 3: Reinstall Slack If the workspace persists, uninstalling Slack and reinstalling it fresh will clear all stored workspaces.

1. Press Win + R, type: appwiz.cpl
2. 
and hit Enter.
3. Find Slack, right-click, and select Uninstall.
4. After uninstalling, go to: %appdata%
5. 
and delete any Slack folder remaining.
6. Reinstall Slack from the official website: https://slack.com/downloads/windows.

After completing these steps, the removed workspace should no longer appear in Slack.