diff --git a/install/user/theme.sh b/install/user/theme.sh
index d2bf915d..e318f5d6 100644
--- a/install/user/theme.sh
+++ b/install/user/theme.sh
@@ -1,13 +1,14 @@
-# Setup user theme folder
+# Setup user theme folder and seed the default only when no theme exists yet.
 mkdir -p ~/.config/omarchy/themes
 
-if [[ ${OMARCHY_SETUP_CONTEXT:-runtime} == "iso-chroot" ]]; then
-  OMARCHY_THEME_HEADLESS=1 omarchy-theme-set "Tokyo Night"
-else
-  omarchy-theme-set "Tokyo Night"
+if [[ ! -s $HOME/.local/state/omarchy/current/theme.name ]]; then
+  if [[ ${OMARCHY_SETUP_CONTEXT:-runtime} == "iso-chroot" ]]; then
+    OMARCHY_THEME_HEADLESS=1 omarchy-theme-set "Tokyo Night"
+    rm -f ~/.config/chromium/SingletonLock # otherwise archiso owns the Chromium singleton
+  else
+    omarchy-theme-set "Tokyo Night"
+  fi
 fi
-
-rm -rf ~/.config/chromium/SingletonLock
 omarchy-theme-set-pi --activate
 
 mkdir -p ~/.config/btop/themes
diff --git a/test/shell.d/user-theme-test.sh b/test/shell.d/user-theme-test.sh
new file mode 100644
index 00000000..0330f931
--- /dev/null
+++ b/test/shell.d/user-theme-test.sh
@@ -0,0 +1,38 @@
+#!/bin/bash
+
+source "$(dirname "$0")/base-test.sh"
+
+test_tmp=$(mktemp -d)
+trap 'rm -rf "$test_tmp"' EXIT
+
+mock_bin="$test_tmp/bin"
+mkdir -p "$mock_bin" "$test_tmp/home/.config/chromium" "$test_tmp/home/.local/state/omarchy/current"
+
+cat >"$mock_bin/omarchy-theme-set" <<'SH'
+#!/bin/bash
+printf '%s\n' "$*" >>"$OMARCHY_TEST_THEME_CALLS"
+SH
+chmod +x "$mock_bin/omarchy-theme-set"
+
+for command in omarchy-theme-set-pi; do
+  cat >"$mock_bin/$command" <<'SH'
+#!/bin/bash
+exit 0
+SH
+  chmod +x "$mock_bin/$command"
+done
+
+calls="$test_tmp/theme-calls"
+touch "$test_tmp/home/.config/chromium/SingletonLock"
+HOME="$test_tmp/home" PATH="$mock_bin:$PATH" OMARCHY_TEST_THEME_CALLS="$calls" \
+  bash "$ROOT/install/user/theme.sh"
+grep -Fx 'Tokyo Night' "$calls" >/dev/null || fail "user theme setup seeds Tokyo Night when no theme exists"
+[[ -f $test_tmp/home/.config/chromium/SingletonLock ]] || fail "runtime user theme setup preserves Chromium's singleton lock"
+
+: >"$calls"
+printf 'Solitude\n' >"$test_tmp/home/.local/state/omarchy/current/theme.name"
+HOME="$test_tmp/home" PATH="$mock_bin:$PATH" OMARCHY_TEST_THEME_CALLS="$calls" \
+  bash "$ROOT/install/user/theme.sh"
+[[ ! -s $calls ]] || fail "user theme setup preserves an existing theme"
+
+pass "user theme setup only seeds the default theme once"