diff --git a/roles/oracle-db-preinstall/tasks/users_configuration.yml b/roles/oracle-db-preinstall/tasks/users_configuration.yml
index e6502b9..e599509 100644
--- a/roles/oracle-db-preinstall/tasks/users_configuration.yml
+++ b/roles/oracle-db-preinstall/tasks/users_configuration.yml
@@ -1,13 +1,21 @@
 ---
-  # --------------------------------------------------- 
+  # ---------------------------------------------------
   # CRéation des groupes
   # ---------------------------------------------------
-  - name: Création des groupes
+  - name: Vérifier si les groupes existent
+    ansible.builtin.getent:
+      database: group
+    register: group_facts
+    ignore_errors: true
+    when: full_configuration |bool
+    tags: group
+
+  - name: Création des groupes (seulement si absents)
     ansible.builtin.group:
       name: "{{ item.group }}"
       gid: "{{ item.gid }}"
       state: present
-    loop: 
+    loop:
         - { group: oinstall, gid: 1001}
         - { group: dba, gid: 1002 }
         - { group: oper, gid: 1003 }
@@ -18,14 +26,21 @@
         - { group: asmadmin, gid: 1008 }
         - { group: asmdba, gid: 1009 }
         - { group: asmoper, gid: 1010 }
-    ignore_errors: true
-    when: full_configuration |bool
+    when: full_configuration |bool and item.group not in (group_facts.ansible_facts.getent_group | default({}))
     tags: group
 
-  # --------------------------------------------------- 
+  # ---------------------------------------------------
   # Création des utilisateurs : password Oracle123 => full configuration
   # ---------------------------------------------------
-  - name: Création du compte Oracle et grid
+  - name: Vérifier si les utilisateurs existent
+    ansible.builtin.getent:
+      database: passwd
+    register: user_facts
+    ignore_errors: true
+    when: full_configuration |bool
+    tags: user
+
+  - name: Création du compte Oracle et grid (seulement si absents)
     ansible.builtin.user:
       name: "{{ item.username }}"
       group: "{{ item.primgroup }}"
@@ -39,8 +54,7 @@
     loop:
     - { username: oracle, uid: 1001, primgroup: oinstall, othergroups: "dba,asmdba,backupdba,dgdba,kmdba,racdba,oper", passwd: "$6$0xHoAXXF$K75HKb64Hcb/CEcr3YEj2LGERi/U2moJgsCK.ztGxLsKoaXc4UBiNZPL0hlxB5ng6GL.gyipfQOOXplzcdgvD0"}
     - { username: grid, uid: 1002, primgroup: oinstall, othergroups: "dba,asmdba,backupdba,dgdba,kmdba,racdba,asmoper,asmadmin", passwd: "$6$0xHoAXXF$K75HKb64Hcb/CEcr3YEj2LGERi/U2moJgsCK.ztGxLsKoaXc4UBiNZPL0hlxB5ng6GL.gyipfQOOXplzcdgvD0"}
-    ignore_errors: true
-    when: full_configuration |bool
+    when: full_configuration |bool and item.username not in (user_facts.ansible_facts.getent_passwd | default({}))
     tags: user