diff --git a/gestioncof/autocomplete.py b/gestioncof/autocomplete.py
index 1eae6920..65f62fab 100644
--- a/gestioncof/autocomplete.py
+++ b/gestioncof/autocomplete.py
@@ -56,22 +56,24 @@ def autocomplete(request):
     # Fetching data from the SPI
     if hasattr(settings, 'LDAP_SERVER_URL'):
         # Fetching
-        ldap_query = '(|{:s})'.format(''.join(
-            ['(cn=*{bit:s}*)(uid=*{bit:s}*)'.format(**{"bit": bit})
-             for bit in bits]
-        ))
-        with Connection(settings.LDAP_SERVER_URL) as conn:
-            conn.search(
-                'dc=spi,dc=ens,dc=fr', ldap_query,
-                attributes=['uid', 'cn']
-            )
-            queries['clippers'] = conn.entries
-        # Clearing redundancies
-        queries['clippers'] = [
-            Clipper(clipper.uid, clipper.cn)
-            for clipper in queries['clippers']
-            if str(clipper.uid) not in usernames
-        ]
+        ldap_query = '(|{:s})'.format(''.join([
+            '(cn=*{bit:s}*)(uid=*{bit:s}*)'.format(bit=bit)
+            for bit in bits if bit.isalnum()
+        ]))
+        if ldap_query != "(|)":
+            # If none of the bits were legal, we do not perform the query
+            with Connection(settings.LDAP_SERVER_URL) as conn:
+                conn.search(
+                    'dc=spi,dc=ens,dc=fr', ldap_query,
+                    attributes=['uid', 'cn']
+                )
+                queries['clippers'] = conn.entries
+            # Clearing redundancies
+            queries['clippers'] = [
+                Clipper(clipper.uid, clipper.cn)
+                for clipper in queries['clippers']
+                if str(clipper.uid) not in usernames
+            ]
 
     # Resulting data
     data.update(queries)
diff --git a/kfet/autocomplete.py b/kfet/autocomplete.py
index 64fa52cf..3b5e0ab5 100644
--- a/kfet/autocomplete.py
+++ b/kfet/autocomplete.py
@@ -75,22 +75,24 @@ def account_create(request):
     # Fetching data from the SPI
     if hasattr(settings, 'LDAP_SERVER_URL'):
         # Fetching
-        ldap_query = '(|{:s})'.format(''.join(
-            ['(cn=*{bit:s}*)(uid=*{bit:s}*)'.format(bit=word)
-             for word in search_words]
-        ))
-        with Connection(settings.LDAP_SERVER_URL) as conn:
-            conn.search(
-                'dc=spi,dc=ens,dc=fr', ldap_query,
-                attributes=['uid', 'cn']
-            )
-            queries['clippers'] = conn.entries
-        # Clearing redundancies
-        queries['clippers'] = [
-            Clipper(clipper.uid, clipper.cn)
-            for clipper in queries['clippers']
-            if str(clipper.uid) not in usernames
-        ]
+        ldap_query = '(|{:s})'.format(''.join([
+            '(cn=*{bit:s}*)(uid=*{bit:s}*)'.format(bit=word)
+            for word in search_words if word.isalnum()
+        ]))
+        if ldap_query != "(|)":
+            # If none of the bits were legal, we do not perform the query
+            with Connection(settings.LDAP_SERVER_URL) as conn:
+                conn.search(
+                    'dc=spi,dc=ens,dc=fr', ldap_query,
+                    attributes=['uid', 'cn']
+                )
+                queries['clippers'] = conn.entries
+            # Clearing redundancies
+            queries['clippers'] = [
+                Clipper(clipper.uid, clipper.cn)
+                for clipper in queries['clippers']
+                if str(clipper.uid) not in usernames
+            ]
 
     # Resulting data
     data.update(queries)