Homebrew/homebrew-cask · warning

Unable to forcibly close VCam.app

Error message

Unable to forcibly close VCam.app

What it means

Printed by the terminate_process step in vcam's postflight_steps (Casks/v/vcam.rb:32). VCam's .pkg postinstall runs `open /Applications/VCam/VCam.app`, so Homebrew follows with `/usr/bin/pkill -f /Applications/VCam/VCam.app` up to 3 times, 1 second apart — note the nested path, because this app installs inside a /Applications/VCam folder (matching the `delete: /Applications/VCam` in the uninstall stanza). pkill exits non-zero when no live process's command line contains that exact nested path; after the last failed attempt Homebrew prints this failure_message as a `Warning:`. With `must_succeed: false` the step never fails the install.

Source

Thrown at Casks/v/vcam.rb:32

  depends_on :macos

  pkg "VCam_#{version}.pkg"

  postflight_steps do
    # Description: Ensure console variant of postinstall is non-interactive.
    # This is because `open /Applications/VCam/VCam.app` is called from the
    # postinstall script of the package and we don't want any user intervention there.
    terminate_process(
      "/Applications/VCam/VCam.app",
      match:           :full,
      attempts:        3,
      must_succeed:    false,
      notices:         [
        "The VCam package postinstall script launches the VCam app",
        "Attempting to close VCam.app to avoid unwanted user intervention",
      ],
      failure_message: "Unable to forcibly close VCam.app",
    )
  end

  uninstall quit:    "ai.vcam.desktop",
            pkgutil: [
              "camera-helper",
              "electron-app",
              "vcam.ai-uninstall",
            ],
            delete:  "/Applications/VCam"

  zap trash: [
    "~/Library/Application Support/com.apple.sharedfilelist/com.apple.LSSharedFileList.ApplicationRecentDocuments/ai.vcam.desktop.sfl*",
    "~/Library/Application Support/com.apple.sharedfilelist/com.apple.LSSharedFileList.ApplicationRecentDocuments/com.splitmedialabs.camerahelper.sfl*",
    "~/Library/Application Support/VCam.ai",
    "~/Library/Preferences/ai.vcam.desktop.plist",
    "~/Library/Saved Application State/ai.vcam.desktop.savedState",
  ]

View on GitHub (pinned to 8587086220)

Solutions

  1. If brew completed, ignore the warning (`must_succeed: false`); quit any leftover app with `pkill -f /Applications/VCam/VCam.app`.
  2. Quit VCam before the operation (`osascript -e 'quit app "VCam"'`), then re-run `brew reinstall --cask vcam`.
  3. For older copies running from a different path, quit them too: `pkill -f VCam.app` (broader match) before installing.
  4. Verify with `pgrep -fl VCam` which path is actually running; if the vendor moved the bundle, update the cask path (`brew edit --cask vcam`) and open a PR.

Example fix

# before
brew upgrade --cask vcam
# Warning: Unable to forcibly close VCam.app

# after: quit the camera app (any install location), then upgrade
osascript -e 'quit app "VCam"' || pkill -f 'VCam.app'
brew upgrade --cask vcam
Defensive patterns

Strategy: validation

Validate before calling

# Quit VCam wherever it runs from (old releases used a non-nested path):
osascript -e 'quit app "VCam"' 2>/dev/null || pkill -f 'VCam.app' 2>/dev/null || true
brew reinstall --cask vcam

Try / catch

begin
  Homebrew::SystemCommand.run!("/usr/bin/pkill", args: ["-f", "/Applications/VCam/VCam.app"])
rescue ErrorDuringExecution
  # No command line contained the nested path: app not running or running
  # from an older non-nested location. Non-fatal by design.
  warn "Unable to forcibly close VCam.app"
end

Prevention

When it happens

Trigger: `brew install|upgrade|reinstall --cask vcam` where all three pkill attempts miss: the app never launched (headless install; postinstall `open` failed), the launch exceeded the ~3s window, or an older VCam release running from a non-nested path (e.g. /Applications/VCam.app) does not match the cask's nested pattern.

Common situations: Upgrades from an older VCam version whose bundle lived directly in /Applications rather than in the VCam folder; SSH/CI installs with no GUI session; slow virtual-camera launch racing the retry window; vendor changing the install layout.

Related errors

AI-assisted analysis of Homebrew/homebrew-cask@8587086220 (2026-08-21). Data as JSON: /api/errors/9f8d5e289b2fdc92. Report an issue: GitHub.