diff --git a/dist/feca_mailshots_plugin-1.0.30.zip b/dist/feca_mailshots_plugin-1.0.30.zip
new file mode 100644
index 0000000..9cdf3f5
Binary files /dev/null and b/dist/feca_mailshots_plugin-1.0.30.zip differ
diff --git a/feca_mailshots_plugin/feca_mailshots_plugin.php b/feca_mailshots_plugin/feca_mailshots_plugin.php
index 33725af..9ab2dc0 100644
--- a/feca_mailshots_plugin/feca_mailshots_plugin.php
+++ b/feca_mailshots_plugin/feca_mailshots_plugin.php
@@ -3,7 +3,7 @@
  * Plugin Name: FECA Mailshots
  * Plugin URI: https://fenedge.co.uk/
  * Description: FECA mailshots plugin.
- * Version: 1.0.29
+ * Version: 1.0.31
  * Requires at least: 6.0
  * Requires PHP: 7.4
  * Author: FECA
diff --git a/feca_mailshots_plugin/src/autoload.php b/feca_mailshots_plugin/src/autoload.php
index 86e3c24..81a73a2 100644
--- a/feca_mailshots_plugin/src/autoload.php
+++ b/feca_mailshots_plugin/src/autoload.php
@@ -8,12 +8,41 @@ $autoloadCandidates = [
     dirname(__DIR__, 2) . '/vendor/autoload.php',    // Backward-compatible: workspace/shared vendor
 ];
 foreach ($autoloadCandidates as $composerAutoload) {
-    if (is_file($composerAutoload)) {
-        require_once $composerAutoload;
+    if (is_file($composerAutoload) && feca_mailshots_composer_autoload_is_usable($composerAutoload)) {
+        try {
+            require_once $composerAutoload;
+        } catch (\Throwable $e) {
+            error_log('FECA Mailshots skipped unusable Composer autoload: ' . $e->getMessage());
+            continue;
+        }
         break;
     }
 }
 
+function feca_mailshots_composer_autoload_is_usable(string $composerAutoload): bool
+{
+    $vendorDir = dirname($composerAutoload);
+    $autoloadFiles = $vendorDir . '/composer/autoload_files.php';
+    if (!is_file($autoloadFiles)) {
+        return true;
+    }
+
+    $files = require $autoloadFiles;
+    if (!is_array($files)) {
+        error_log('FECA Mailshots Composer autoload_files.php did not return an array.');
+        return false;
+    }
+
+    foreach ($files as $file) {
+        if (!is_string($file) || !is_file($file)) {
+            error_log('FECA Mailshots Composer dependency file is missing: ' . (is_scalar($file) ? (string) $file : 'unknown'));
+            return false;
+        }
+    }
+
+    return true;
+}
+
 spl_autoload_register(static function (string $class): void {
     $prefix = 'FecaMailshots\\';
     if (strncmp($class, $prefix, strlen($prefix)) !== 0) {
diff --git a/scripts/deploy_remote.sh b/scripts/deploy_remote.sh
index 83dda37..65d1f17 100755
--- a/scripts/deploy_remote.sh
+++ b/scripts/deploy_remote.sh
@@ -174,6 +174,7 @@ else
     echo "Error: ${LOCAL_VENDOR_DIR}/autoload.php is missing. Install dependencies first (scripts/install_dependencies.sh)." >&2
     exit 1
   fi
+  php "${REPO_ROOT}/scripts/validate_composer_vendor.php" "${LOCAL_VENDOR_DIR}"
 fi
 
 ssh -p "${SSH_PORT}" \
@@ -217,5 +218,11 @@ rsync "${VENDOR_RSYNC_ARGS[@]}" \
 if [[ "${DRY_RUN}" -eq 1 ]]; then
   echo "Dry-run complete. No remote files were changed."
 else
+  ssh -p "${SSH_PORT}" \
+    -i "${SSH_KEY_PATH}" \
+    -o BatchMode=yes \
+    -o StrictHostKeyChecking=accept-new \
+    "${SSH_TARGET}" \
+    "test -f '${REMOTE_DIR}/vendor/autoload.php' && test -f '${REMOTE_DIR}/vendor/thecodingmachine/safe/lib/special_cases.php'"
   echo "Deploy complete."
 fi
diff --git a/scripts/package_plugin.sh b/scripts/package_plugin.sh
index b187c0a..77c1f55 100755
--- a/scripts/package_plugin.sh
+++ b/scripts/package_plugin.sh
@@ -94,6 +94,7 @@ if [[ ! -f "${REPO_ROOT}/vendor/autoload.php" ]]; then
   echo "Error: vendor/autoload.php is missing after dependency install." >&2
   exit 1
 fi
+php "${REPO_ROOT}/scripts/validate_composer_vendor.php" "${REPO_ROOT}/vendor"
 
 rsync -a \
   --delete \
@@ -108,6 +109,7 @@ rsync -a \
 
 mkdir -p "${STAGE_DIR}/vendor"
 rsync -a --delete "${REPO_ROOT}/vendor/" "${STAGE_DIR}/vendor/"
+php "${REPO_ROOT}/scripts/validate_composer_vendor.php" "${STAGE_DIR}/vendor"
 
 ARCHIVE_PATH="${OUTPUT_DIR}/${PLUGIN_BASENAME}-${VERSION}.zip"
 rm -f "${ARCHIVE_PATH}"
diff --git a/scripts/validate_composer_vendor.php b/scripts/validate_composer_vendor.php
new file mode 100644
index 0000000..31ca3da
--- /dev/null
+++ b/scripts/validate_composer_vendor.php
@@ -0,0 +1,39 @@
+<?php
+
+declare(strict_types=1);
+
+$vendorDir = isset($argv[1]) ? rtrim((string) $argv[1], '/') : dirname(__DIR__) . '/vendor';
+$autoload = $vendorDir . '/autoload.php';
+$autoloadFiles = $vendorDir . '/composer/autoload_files.php';
+
+if (!is_file($autoload)) {
+    fwrite(STDERR, "Missing Composer autoload: {$autoload}\n");
+    exit(1);
+}
+
+if (!is_file($autoloadFiles)) {
+    exit(0);
+}
+
+$files = require $autoloadFiles;
+if (!is_array($files)) {
+    fwrite(STDERR, "Composer autoload files map did not return an array: {$autoloadFiles}\n");
+    exit(1);
+}
+
+$missing = [];
+foreach ($files as $file) {
+    if (!is_string($file) || !is_file($file)) {
+        $missing[] = is_scalar($file) ? (string) $file : 'unknown';
+    }
+}
+
+if ($missing !== []) {
+    fwrite(STDERR, "Composer vendor is incomplete; missing files:\n");
+    foreach ($missing as $file) {
+        fwrite(STDERR, " - {$file}\n");
+    }
+    exit(1);
+}
+
+exit(0);