This article explains how to log out of a Slack team using a computer. Since your account is linked to your team workspace, you need to deactivate your profile.
Steps
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Step 1. Log in to Slack
If you are using the desktop application, click on the icon in the Windows menu (PC) or in the Applications folder (Mac). To use the browser version, log in by entering your team's URL in the address bar.
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Step 2. Click on the team name
It is located in the upper left.
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Step 3. Click on Profile & Account
It's at the top of the menu.
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Step 4. Click on the gear icon
It's in the far right column, under your username.
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Step 5. Click Deactivate your account
This option is at the bottom of the list. A confirmation message will appear.
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Step 6. Click Yes, deactivate my account
At this point a screen will appear asking you to confirm if you want to remove your account from this team.
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Step 7. Check the box next to "Yes, I want to deactivate my account"
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Step 8. Click Deactivate my account
Your account will then be deactivated.