diff --git a/PRODUCTION-FIX-GUIDE.md b/PRODUCTION-FIX-GUIDE.md
index 5875fe1..088332d 100644
--- a/PRODUCTION-FIX-GUIDE.md
+++ b/PRODUCTION-FIX-GUIDE.md
@@ -54,7 +54,11 @@ Si l'interface affiche "Aucun utilisateur trouvé" :
 ### Problème Création d'Utilisateur
 
 #### Erreur "duplicate key value violates unique constraint users_email_key"
-Cette erreur survient quand plusieurs utilisateurs ont un email vide (`""`) car PostgreSQL traite les chaînes vides comme des valeurs uniques.
+Cette erreur survient lors de la **création** ou **édition** d'utilisateur quand plusieurs utilisateurs ont un email vide (`""`) car PostgreSQL traite les chaînes vides comme des valeurs uniques.
+
+**Symptômes** :
+- Création d'utilisateur échoue avec erreur `Key (email)=() already exists`
+- Édition d'utilisateur échoue avec la même erreur lors de la sauvegarde
 
 **Solution** :
 1. Exécutez le script de correction :
@@ -62,7 +66,7 @@ Cette erreur survient quand plusieurs utilisateurs ont un email vide (`""`) car
    psql $DATABASE_URL -f fix-duplicate-empty-email.sql
    ```
 
-2. Redéployez l'application (le code a été corrigé pour utiliser `NULL` au lieu de `""`)
+2. Redéployez l'application (le code a été corrigé pour utiliser `NULL` au lieu de `""` dans les routes de création ET d'édition)
 
 #### Tests de Création
 1. **Test Manuel** : Utilisez `test-create-user-production.js`
diff --git a/attached_assets/image_1754943064930.png b/attached_assets/image_1754943064930.png
new file mode 100644
index 0000000..965c97b
Binary files /dev/null and b/attached_assets/image_1754943064930.png differ
diff --git a/replit.md b/replit.md
index 52b91df..3331430 100644
--- a/replit.md
+++ b/replit.md
@@ -139,4 +139,14 @@ Preferred communication style: Simple, everyday language.
 - **Issue**: Admin password changes failed in production with ERR_MODULE_NOT_FOUND for localAuth.production
 - **Root Cause**: Dynamic imports in production needed `.js` extension for compiled files
 - **Solution**: Updated import paths to use `./localAuth.production.js` for production environment
-- **Result**: Password hashing now works correctly in production for user updates
\ No newline at end of file
+- **Result**: Password hashing now works correctly in production for user updates
+
+#### Email Constraint Fix for User Management
+- **Issue**: Both user creation and editing failed with "duplicate key value violates unique constraint users_email_key" error
+- **Root Cause**: PostgreSQL treats empty strings (`""`) as unique values, but multiple users with empty emails violated uniqueness constraint
+- **Solution Implemented**:
+  - Updated both POST `/api/users` (creation) and PUT `/api/users/:id` (editing) routes to convert empty emails to `NULL`
+  - Enhanced validation schemas to accept `null` values for email fields
+  - Created `fix-duplicate-empty-email.sql` script to clean existing database records
+  - Improved error handling and logging for better production debugging
+- **Result**: Users can now be created and edited with optional email fields without constraint violations
\ No newline at end of file
diff --git a/server/routes.ts b/server/routes.ts
index 6c7a5b1..04ae466 100644
--- a/server/routes.ts
+++ b/server/routes.ts
@@ -1001,8 +1001,12 @@ export async function registerRoutes(app: Express): Promise<Server> {
 
   app.put('/api/users/:id', isAuthenticated, async (req: any, res) => {
     try {
+      console.log('🔍 PUT /api/users/:id - Updating user:', req.params.id);
+      console.log('📥 Update data:', JSON.stringify(req.body, null, 2));
+      
       const user = await storage.getUserWithGroups(req.user.claims ? req.user.claims.sub : req.user.id);
       if (!user || user.role !== 'admin') {
+        console.log('❌ Access denied - user not admin');
         return res.status(403).json({ message: "Access denied" });
       }
 
@@ -1010,26 +1014,49 @@ export async function registerRoutes(app: Express): Promise<Server> {
       const updateUserSchema = z.object({
         username: z.string().optional(),
         role: z.enum(['admin', 'directeur', 'manager', 'employee']).optional(),
-        firstName: z.union([z.string(), z.literal("")]).optional(),
-        lastName: z.union([z.string(), z.literal("")]).optional(),
-        email: z.union([z.string().email(), z.literal("")]).optional(),
+        firstName: z.union([z.string(), z.literal(""), z.null()]).optional(),
+        lastName: z.union([z.string(), z.literal(""), z.null()]).optional(),
+        email: z.union([z.string().email(), z.literal(""), z.null()]).optional(),
         password: z.string().optional(),
       });
 
+      console.log('🔍 Parsing update data...');
       const userData = updateUserSchema.parse(req.body);
+      console.log('✅ Update data parsed successfully');
       
-      // Hash password if provided
-      if (userData.password) {
-        userData.password = await hashPasswordSimple(userData.password);
-        // Mark password as changed
-        (userData as any).passwordChanged = true;
+      // Clean up the data - handle empty emails properly
+      const cleanUserData: any = { ...userData };
+      
+      // Handle email field - convert empty string to null
+      if (cleanUserData.email !== undefined) {
+        cleanUserData.email = cleanUserData.email && cleanUserData.email.trim() !== '' ? cleanUserData.email : null;
+        console.log('🔍 Email field processed:', cleanUserData.email === null ? 'NULL' : cleanUserData.email);
       }
       
-      const updatedUser = await storage.updateUser(req.params.id, userData);
+      // Hash password if provided
+      if (cleanUserData.password) {
+        try {
+          console.log('🔒 Hashing password...');
+          cleanUserData.password = await hashPasswordSimple(cleanUserData.password);
+          cleanUserData.passwordChanged = true;
+          console.log('✅ Password hashed successfully');
+        } catch (hashError) {
+          console.error('❌ Password hashing failed:', hashError);
+          return res.status(500).json({ message: "Failed to secure password" });
+        }
+      }
+      
+      console.log('🔍 Updating user in database...');
+      const updatedUser = await storage.updateUser(req.params.id, cleanUserData);
+      console.log('✅ User updated successfully:', updatedUser.username);
 
       res.json(updatedUser);
     } catch (error: any) {
-      console.error("Error updating user:", error);
+      console.error("❌ Error updating user:", error);
+      console.error("❌ Error type:", error.constructor.name);
+      console.error("❌ Error code:", error.code);
+      console.error("❌ Error constraint:", error.constraint);
+      console.error("❌ Error stack:", error.stack);
       
       if (error instanceof z.ZodError) {
         return res.status(400).json({ message: "Invalid user data", errors: error.errors });
diff --git a/server/storage.ts b/server/storage.ts
index 333218c..5bbc53a 100644
--- a/server/storage.ts
+++ b/server/storage.ts
@@ -317,15 +317,25 @@ export class DatabaseStorage implements IStorage {
   }
 
   async updateUser(id: string, userData: Partial<UpsertUser>): Promise<User> {
-    const [user] = await db
-      .update(users)
-      .set({
-        ...userData,
-        updatedAt: new Date(),
-      })
-      .where(eq(users.id, id))
-      .returning();
-    return user;
+    console.log('🔍 Storage updateUser called for:', id);
+    console.log('🔍 Update data:', userData);
+    try {
+      const [user] = await db
+        .update(users)
+        .set({
+          ...userData,
+          updatedAt: new Date(),
+        })
+        .where(eq(users.id, id))
+        .returning();
+      console.log('✅ Storage updateUser successful:', user.username);
+      return user;
+    } catch (error) {
+      console.error('❌ Storage updateUser error:', error);
+      console.error('❌ Storage error code:', error.code);
+      console.error('❌ Storage error constraint:', error.constraint);
+      throw error;
+    }
   }
 
   async deleteUser(id: string): Promise<void> {