diff --git a/src/main/java/org/olat/group/ui/main/BusinessGroupSearchController.java b/src/main/java/org/olat/group/ui/main/BusinessGroupSearchController.java
index deab7c527763f319de8eebbc76927d65b9114122..6a677f9a74a0514d072b4874ab98601ab26ebe91 100644
--- a/src/main/java/org/olat/group/ui/main/BusinessGroupSearchController.java
+++ b/src/main/java/org/olat/group/ui/main/BusinessGroupSearchController.java
@@ -216,7 +216,7 @@ public class BusinessGroupSearchController extends FormBasicController implement
 				try {
 					new Long(id.getValue());
 				} catch (NumberFormatException e) {
-					id.setErrorKey("", null);
+					id.setErrorKey("search.id.format", null);
 					allOk &= false;
 				}
 			}
diff --git a/src/main/java/org/olat/group/ui/main/_i18n/LocalStrings_de.properties b/src/main/java/org/olat/group/ui/main/_i18n/LocalStrings_de.properties
index 1bfd6763b56104bbddaf9f47ddcac0f5b94c865d..a6a0f2aba57a387d69a22bf45744351aec4005f1 100644
--- a/src/main/java/org/olat/group/ui/main/_i18n/LocalStrings_de.properties
+++ b/src/main/java/org/olat/group/ui/main/_i18n/LocalStrings_de.properties
@@ -51,6 +51,7 @@ search.no=Nein
 search.resources=In Kursen verwendet
 search.headless=Orphans
 search.headless.check=Gruppe ohne Mitglieder und Ressourcen
+search.id.format=Keine g\u00FCltige Gruppen-ID
 cif.displayname=Name
 cif.description=Beschreibung
 cif.owner=Betreuer