diff --git a/install-nightly.sh b/install-nightly.sh
index c12883c..c1b4e1a 100755
--- a/install-nightly.sh
+++ b/install-nightly.sh
@@ -256,7 +256,11 @@ info "🔧 Setting up Python virtual environment …"
 VENV_DIR="${INSTALL_DIR}/.venv"
 REQUIREMENTS="${INSTALL_DIR}/requirements.txt"
 
-if [ ! -f "$VENV_DIR/bin/python3" ]; then
+# A venv is usable only if python3 AND pip both work. Ubuntu's `python3 -m venv`
+# without the python3-venv package leaves a venv with python3 but no pip — detect
+# that and recreate, so a broken venv never survives a restart.
+if [ ! -f "$VENV_DIR/bin/python3" ] || ! "$VENV_DIR/bin/python3" -m pip --version >/dev/null 2>&1; then
+    rm -rf "$VENV_DIR"
     if command -v uv >/dev/null 2>&1; then
         uv venv --seed "$VENV_DIR" && uv pip install -r "$REQUIREMENTS" \
             && info "✔ Python venv ready (uv)" \
diff --git a/install.sh b/install.sh
index 60b6f83..596a436 100755
--- a/install.sh
+++ b/install.sh
@@ -261,7 +261,11 @@ info "🔧 Setting up Python virtual environment …"
 VENV_DIR="${INSTALL_DIR}/.venv"
 REQUIREMENTS="${INSTALL_DIR}/requirements.txt"
 
-if [ ! -f "$VENV_DIR/bin/python3" ]; then
+# A venv is usable only if python3 AND pip both work. Ubuntu's `python3 -m venv`
+# without the python3-venv package leaves a venv with python3 but no pip — detect
+# that and recreate, so a broken venv never survives a restart.
+if [ ! -f "$VENV_DIR/bin/python3" ] || ! "$VENV_DIR/bin/python3" -m pip --version >/dev/null 2>&1; then
+    rm -rf "$VENV_DIR"
     if command -v uv >/dev/null 2>&1; then
         uv venv --seed "$VENV_DIR" && uv pip install -r "$REQUIREMENTS" \
             && info "✔ Python venv ready (uv)" \
diff --git a/run-docker.sh b/run-docker.sh
index af33a4a..5dc04f8 100644
--- a/run-docker.sh
+++ b/run-docker.sh
@@ -11,7 +11,11 @@ cd "$(dirname "$0")"
 VENV_DIR=".venv"
 REQUIREMENTS="requirements.txt"
 
-if [ ! -f "$VENV_DIR/bin/python3" ] && [ -f "$REQUIREMENTS" ]; then
+# A venv is usable only if python3 AND pip both work. Ubuntu's `python3 -m venv`
+# without the python3-venv package leaves a venv with python3 but no pip — detect
+# that and recreate, so a broken venv never survives a restart.
+if [ -f "$REQUIREMENTS" ] && { [ ! -f "$VENV_DIR/bin/python3" ] || ! "$VENV_DIR/bin/python3" -m pip --version >/dev/null 2>&1; }; then
+    rm -rf "$VENV_DIR"
     if command -v uv >/dev/null 2>&1; then
         echo "[run-docker.sh] Setting up Python venv with uv …"
         uv venv --seed "$VENV_DIR" && uv pip install -r "$REQUIREMENTS" \
diff --git a/run.sh b/run.sh
index 7a78469..70a9ada 100755
--- a/run.sh
+++ b/run.sh
@@ -50,7 +50,11 @@ fi
 VENV_DIR=".venv"
 REQUIREMENTS="requirements.txt"
 
-if [ ! -f "$VENV_DIR/bin/python3" ]; then
+# A venv is usable only if python3 AND pip both work. Ubuntu's `python3 -m venv`
+# without the python3-venv package leaves a venv with python3 but no pip — detect
+# that and recreate, so a broken venv never survives a restart.
+if [ ! -f "$VENV_DIR/bin/python3" ] || ! "$VENV_DIR/bin/python3" -m pip --version >/dev/null 2>&1; then
+    rm -rf "$VENV_DIR"
     if command -v uv >/dev/null 2>&1; then
         echo "[run.sh] Setting up Python venv with uv …"
         uv venv --seed "$VENV_DIR" && uv pip install -r "$REQUIREMENTS" \