diff --git a/README.md b/README.md
index 621eaa2..638cc10 100644
--- a/README.md
+++ b/README.md
@@ -102,6 +102,11 @@ Die grundlegende Funktionalität wurde mit folgenden Komponenten implementiert:
 - `scripts/powershell/create_user.ps1`: PowerShell-Skript zum Erstellen eines einzelnen Benutzers.
 - `scripts/powershell/create_users_csv.ps1`: PowerShell-Skript zum Erstellen mehrerer Benutzer aus CSV.
 
+- `scripts/powershell/check_environment.ps1`: Prüft, ob `ActiveDirectory`-Modul vorhanden ist und zeigt die ausführende Identität an.
+
+API endpoints:
+- `public/api/powershell_check.php`: Ruft `check_environment.ps1` auf und gibt ein JSON-Objekt mit `actor`, `module_installed`, `can_new_aduser` zurück.
+
 Bitte testen zuerst mit `powershell.dry_run = true` und prüfen sie die resultierenden Meldungen in UI.
 
 
diff --git a/public/api/powershell_check.php b/public/api/powershell_check.php
new file mode 100644
index 0000000..bd10313
--- /dev/null
+++ b/public/api/powershell_check.php
@@ -0,0 +1,45 @@
+<?php
+declare(strict_types=1);
+
+session_start();
+
+// Load config
+$config = require __DIR__ . '/../../config/config.php';
+
+// Simple login check (same as index.php)
+$sessionKey = $config['security']['session_key_user'] ?? 'admin_user';
+if (!isset($_SESSION[$sessionKey])) {
+    header('Content-Type: application/json');
+    echo json_encode(['success' => false, 'message' => 'Not authenticated']);
+    exit;
+}
+
+$scriptDir = $config['powershell']['script_dir'] ?? __DIR__ . '/../../scripts/powershell';
+$script = $scriptDir . DIRECTORY_SEPARATOR . 'check_environment.ps1';
+$exe = $config['powershell']['exe'] ?? 'powershell';
+$executionPolicy = $config['powershell']['execution_policy'] ?? 'Bypass';
+
+if (!file_exists($script)) {
+    header('Content-Type: application/json');
+    echo json_encode(['success' => false, 'message' => 'Script not found: ' . $script]);
+    exit;
+}
+
+$cmd = sprintf('%s -NoProfile -NonInteractive -ExecutionPolicy %s -File "%s"', $exe, $executionPolicy, $script);
+
+$output = [];
+$returnVar = null;
+exec($cmd . ' 2>&1', $output, $returnVar);
+$json = implode("\n", $output);
+
+// Attempt to parse JSON
+$decoded = json_decode($json, true);
+if ($decoded === null) {
+    header('Content-Type: application/json');
+    echo json_encode(['success' => false, 'message' => 'Invalid JSON output', 'raw' => $json]);
+    exit;
+}
+
+header('Content-Type: application/json');
+echo json_encode($decoded);
+exit;
diff --git a/scripts/powershell/check_environment.ps1 b/scripts/powershell/check_environment.ps1
new file mode 100644
index 0000000..811cdea
--- /dev/null
+++ b/scripts/powershell/check_environment.ps1
@@ -0,0 +1,17 @@
+# Returns JSON with information about the environment and AD module availability
+Try {
+    $actor = [System.Security.Principal.WindowsIdentity]::GetCurrent().Name
+} Catch {
+    $actor = $null
+}
+
+# Does the ActiveDirectory module exist?
+$module = Get-Module -ListAvailable -Name ActiveDirectory -ErrorAction SilentlyContinue
+$hasModule = $module -ne $null
+
+# Is New-ADUser available?
+$canNewAdUser = (Get-Command New-ADUser -ErrorAction SilentlyContinue) -ne $null
+
+$output = @{ success = $true; actor = $actor; module_installed = $hasModule; can_new_aduser = $canNewAdUser }
+Write-Output ($output | ConvertTo-Json -Compress)
+exit 0
diff --git a/scripts/powershell/create_users_csv.ps1 b/scripts/powershell/create_users_csv.ps1
index af438a3..7f1782a 100644
--- a/scripts/powershell/create_users_csv.ps1
+++ b/scripts/powershell/create_users_csv.ps1
@@ -13,7 +13,10 @@ try {
 }
 
 $csvFile = [string]$meta.input_file
-$delimiter = [string]($meta.delimiter ?? ',')
+# PowerShell 5.1 doesn't support the null-coalescing operator '??'.
+# Use an explicit check here to set the default delimiter.
+$delimiter = [string]$meta.delimiter
+if ([string]::IsNullOrWhiteSpace($delimiter)) { $delimiter = ',' }
 $hasHeader = [bool]($meta.has_header -as [bool])
 $dryRun = [bool]($meta.dry_run -as [bool])