diff --git a/classic-commerce.php b/classic-commerce.php
index 745ceafa69..5d1c74ae34 100644
--- a/classic-commerce.php
+++ b/classic-commerce.php
@@ -38,6 +38,27 @@ function cc_wc_already_active_notice() {
 	echo '</div>';
 }
 
+/**
+ * Shows an error message when Classic Commerce is active and the user attempts
+ * to activate WooCommerce.
+ *
+ * WooCommerce and Classic Commerce cannot both be active at once.
+ *
+ * @return void
+ */
+function cc_wc_activate_attempted_notice() {
+	echo '<div class="notice error is-dismissible">';
+	echo '<p><strong>';
+	echo esc_html__( 'You must deactivate Classic Commerce before activating WooCommerce.', 'classic-commerce' );
+	echo '</strong></p>';
+	echo '<p>';
+	echo esc_html__( 'WooCommerce has not been activated.', 'classic-commerce' );
+	echo '</p>';
+	echo '</div>';
+}
+
+$_cc_can_load = true;
+
 // Check if WooCommerce is already active.  In this case we need to block
 // Classic Commerce from being activated to avoid fatal errors.
 if (
@@ -58,8 +79,64 @@ function cc_wc_already_active_notice() {
 	unset( $_GET['activate'] );
 
 	// Do not proceed further with Classic Commerce loading.
+	$_cc_can_load = false;
+
+} else if (
+	// Check if this is a request that would activate WooCommerce.  Since
+	// Classic Commerce is already active then we also need to prevent
+	// WooCommerce from being activated, again to avoid fatal errors.
+	//
+	// Plugin activation happens after plugins load and after `init` so we need
+	// to check for the presence of the related request parameters here.
+	//
+	// See also src/wp-admin/plugins.php in core.
+	is_admin() &&
+	strpos( $_SERVER['REQUEST_URI'], '/plugins.php' ) !== false &&
+	( isset( $_REQUEST['action'] ) || isset( $_REQUEST['action2'] ) ) &&
+	// Make sure we are really looking at WooCommerce and not the compatibility plugin!
+	file_exists( WP_PLUGIN_DIR . '/woocommerce/includes/class-woocommerce.php' )
+) {
+	$is_activate_woo_request = false;
+
+	// Check if the user tried to activate WooCommerce by itself.
+	if (
+		isset( $_GET['action'] ) &&
+		$_GET['action'] === 'activate' &&
+		isset( $_GET['plugin'] ) &&
+		$_GET['plugin'] === 'woocommerce/woocommerce.php'
+	) {
+		$is_activate_woo_request = true;
+	}
+
+	// Check if the user tried to activate WooCommerce using either of the two
+	// "Bulk Actions" dropdown boxes.
+	if (
+		(
+			( isset( $_POST['action'] ) && $_POST['action'] === 'activate-selected' ) ||
+			( isset( $_POST['action2'] ) && $_POST['action2'] === 'activate-selected' )
+		) &&
+		isset( $_POST['checked'] ) &&
+		in_array( 'woocommerce/woocommerce.php', (array) wp_unslash( $_POST['checked'] ) )
+	) {
+		$is_activate_woo_request = true;
+	}
+
+	if ( $is_activate_woo_request ) {
+		// Show an admin notice.
+		add_action( 'admin_notices', 'cc_wc_activate_attempted_notice' );
+
+		// Block WooCommerce from being activated.
+		unset( $_GET['action'] );
+		unset( $_POST['action'] );
+		unset( $_REQUEST['action'] );
+		unset( $_POST['action2'] );
+		unset( $_REQUEST['action2'] );
+
+		// Proceed normally with the Classic Commerce loading process below.
+	}
+}
 
-} else {
+if ( $_cc_can_load ) {
 
 	////////////////////////////////////////////
 	// BEGIN CLASSIC COMMERCE LOADING PROCESS //