How to Resolve the "Corrupt Installation" Warning with Custom UI Style and Islands Dark

Dismiss the warning by clicking the gear icon on the banner and selecting "Don't Show Again" after enabling the Custom UI Style extension—it is expected, harmless, and will not reappear once suppressed.

The Islands Dark theme in the bwya77/vscode-dark-islands repository delivers its distinctive rounded UI by pairing a VS Code color theme with the Custom UI Style extension (subframe7536.custom-ui-style). When this extension loads the CSS stylesheet defined in your user settings, VS Code detects the modification to its core UI and triggers a "corrupt installation" warning on first activation. This notification is standard behavior for any extension that injects styles into the workbench, and resolving it requires a single user interaction to acknowledge the third-party modification.

Why VS Code Flags the Islands Dark Theme as Corrupt

The warning appears because the Custom UI Style extension modifies VS Code's internal DOM. In settings.json, the theme configures a custom-ui-style.stylesheet object that defines CSS custom properties under the .monaco-workbench selector:

{
  "custom-ui-style.stylesheet": {
    ".monaco-workbench": {
      "--islands-panel-radius": "24px",
      "--islands-widget-radius": "14px",
      "--islands-bg-canvas": "#121216",
      "background-color": "var(--islands-bg-canvas) !important"
    }
  }
}

When the extension activates, it injects this CSS directly into the workbench HTML. VS Code treats this as an external modification of its installation files and displays the corruption warning to alert users that the UI has been altered from its default state. This occurs only on the first reload after enabling the extension or updating the stylesheet.

Step-by-Step Resolution

Follow these steps to resolve the warning and maintain the Islands Dark aesthetic.

Install the Required Extension

The repository provides automated installation scripts that handle the dependency automatically. Both install.sh and install.ps1 execute the command:

code --install-extension subframe7536.custom-ui-style --force

If you prefer manual installation, search for Custom UI Style by subframe7536 in the Extensions marketplace and install it before proceeding.

Enable Custom UI Style and Reload

Open the Command Palette (Ctrl+Shift+P or Cmd+Shift+P) and run "Custom UI Style: Install". This command patches VS Code's core files to allow CSS injection and triggers a mandatory reload. Upon restart, the extension applies the stylesheet rules contained in settings.json.

Dismiss the Warning Permanently

After the reload completes, VS Code displays a yellow warning banner stating that the installation is corrupt. Click the gear icon on the right side of the banner and select "Don't Show Again". This action records your preference in VS Code's internal state, preventing the notification from appearing on subsequent launches while preserving the injected styling.

Verifying the Configuration

If the warning persists or styles fail to apply, verify that your settings.json contains the merged configuration. The repository includes merge-settings.ps1, which performs a deep merge of the theme's stylesheet object into your existing user settings:

$stylesheetKey = 'custom-ui-style.stylesheet'
if ($settingsJson.ContainsKey($stylesheetKey)) {
    $target[$stylesheetKey] = $settingsJson[$stylesheetKey]
}

Ensure the final configuration in your user settings.json includes both the theme declaration and the stylesheet object:

{
  "workbench.colorTheme": "Islands Dark",
  "custom-ui-style.stylesheet": {
    ".monaco-workbench": {
      "--islands-panel-radius": "24px",
      "--islands-bg-canvas": "#121216",
      "background-color": "var(--islands-bg-canvas) !important"
    }
  },
  "editor.fontFamily": "Bear Sans UI, IBM Plex Mono, FiraCode Nerd Font Mono"
}

Key files in the bwya77/vscode-dark-islands repository that manage this integration include settings.json (default configuration), merge-settings.ps1 (settings merger), and themes/islands-dark.json (color definitions).

Summary

• The "corrupt installation" warning is generated by VS Code when the Custom UI Style extension injects CSS into the workbench via custom-ui-style.stylesheet in settings.json.
• Resolution requires clicking the gear icon on the warning banner and selecting "Don't Show Again" after the first reload.
• The install scripts (install.sh, install.ps1) automatically install subframe7536.custom-ui-style using the --force flag.
• The merge script (merge-settings.ps1) handles deep merging of the CSS configuration to prevent JSON conflicts.
• Once dismissed, the warning will not reappear unless you reinstall VS Code or clear your user state.

Frequently Asked Questions

Is the corrupt installation warning dangerous?

No. The warning indicates that the Custom UI Style extension has modified VS Code's internal CSS layout to apply the Islands Dark aesthetic. This is an expected and harmless side effect of the extension's architecture. Dismissing the warning allows you to use the theme normally without security or stability risks.

Do I need to manually edit settings.json to fix the warning?

No manual editing is required to resolve the warning itself. The automated merge-settings.ps1 script ensures your settings.json contains the correct custom-ui-style.stylesheet configuration. However, you may edit the CSS properties within settings.json to adjust variables like --islands-panel-radius or --islands-bg-canvas without triggering the warning again.

Why does the warning reappear after I update VS Code?

Major VS Code updates sometimes reset the internal flag that suppresses the corruption notice. If the warning returns after an update, simply repeat the dismissal process: click the gear icon on the banner and select "Don't Show Again." Your Custom UI Style settings remain intact, and the extension will continue to inject the stylesheet defined in your user configuration.

Can I use Islands Dark without the Custom UI Style extension?

You can activate the Islands Dark color theme from themes/islands-dark.json without the extension, but you will not see the custom-rounded panels, background colors, or layout spacing that define the theme's visual identity. The extension is required to apply the CSS custom properties that create the signature "island" aesthetic.

{
  "mcpServers": {
    "instagit": {
      "command": "npx",
      "args": ["-y", "instagit@latest"]
    }
  }
}