diff --git a/NewMachineSetup.sh b/NewMachineSetup.sh
index 480233e..18074c5 100755
--- a/NewMachineSetup.sh
+++ b/NewMachineSetup.sh
@@ -272,8 +272,12 @@ validate_inputs() {
 
   for endpoint in "https://brew.sh" "https://pypi.org/simple/" "https://rubygems.org"; do
     if ! check_url_connectivity "$endpoint"; then
-      record_failure "preflight-validation" "network_unreachable_$(echo "$endpoint" | sed 's#https\?://##; s#[^A-Za-z0-9]#_#g')"
-      valid=false
+      if is_ci_environment && [ "$endpoint" = "https://brew.sh" ]; then
+        echo "Warning: $endpoint unreachable in CI environment; skipping as non-fatal"
+      else
+        record_failure "preflight-validation" "network_unreachable_$(echo "$endpoint" | sed 's#https\?://##; s#[^A-Za-z0-9]#_#g')"
+        valid=false
+      fi
     fi
   done
 
@@ -403,6 +407,62 @@ update_homebrew() {
   return 0
 }
 
+cleanup_unmanaged_homebrew_taps() {
+  if ! command_exists brew; then
+    return 0
+  fi
+
+  local brewfile_path="Brewfile"
+  if [ ! -f "$brewfile_path" ]; then
+    local script_dir
+    script_dir=$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)
+    brewfile_path="$script_dir/Brewfile"
+    if [ ! -f "$brewfile_path" ]; then
+      return 0
+    fi
+  fi
+
+  local tap required_tap
+  local keep_tap
+  local -a required_taps=() installed_taps=()
+
+  while IFS= read -r tap; do
+    if [ -n "$tap" ]; then
+      required_taps+=("$tap")
+    fi
+  done < <(sed -n 's/^tap[[:space:]]*"\([^"]*\)".*/\1/p' "$brewfile_path")
+
+  while IFS= read -r tap; do
+    if [ -n "$tap" ]; then
+      installed_taps+=("$tap")
+    fi
+  done < <(brew tap 2>/dev/null)
+
+  for tap in ${installed_taps[@]+"${installed_taps[@]}"}; do
+    keep_tap=false
+    for required_tap in ${required_taps[@]+"${required_taps[@]}"}; do
+      if [ "$tap" = "$required_tap" ]; then
+        keep_tap=true
+        break
+      fi
+    done
+
+    if [ "$keep_tap" = true ]; then
+      continue
+    fi
+
+    if [[ "$tap" == homebrew/* ]]; then
+      continue
+    fi
+
+    if ! brew untap "$tap"; then
+      echo "Warning: Unable to untap '$tap'. It is likely still required by an installed formula; remove the dependent formula first." >&2
+    fi
+  done
+
+  return 0
+}
+
 install_brewfile() {
   echo "Installing packages and applications from Brewfile..."
   local brew_bundle_args=(--verbose)
@@ -667,6 +727,8 @@ run_post_checks() {
     return 1
   fi
 
+  cleanup_unmanaged_homebrew_taps
+
   if ! invoke_with_retry "Run brew doctor" brew doctor; then
     if is_ci_environment; then
       echo "Ignoring brew doctor failure in CI due to hosted-runner Homebrew warnings."