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Login as Jira Administrator
Click the cog icon icon on the left bar to open the Jira administration console.
Via 'Add-ons' > 'Manage add-ons' tab in the left menu, you will see all apps installed on your Jira instance.
Click the JSU app. The details for the JSU app will display.
Click the 'Uninstall' button. The information summary will display an 'Uninstalling' message and the app will be uninstalled from Jira.
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You can remove and re-install JSU without the loss of configuration made.
All implemented features "stay" in your workflows and therefore will be available again after the re-installation.
Be aware that if you want to permanently remove JSU from your instance, you first have to remove all implemented JSU features from your workflows. See the JSU Configuration Guide for the list of all modules of JSU, which that you might have to remove.