diff --git a/lam/lib/modules/posixAccount.inc b/lam/lib/modules/posixAccount.inc
index eea1d284..b2113ae4 100644
--- a/lam/lib/modules/posixAccount.inc
+++ b/lam/lib/modules/posixAccount.inc
@@ -758,17 +758,19 @@ class posixAccount extends baseModule {
 			// old account -> return id-number which has been used
 		}
 		else {
-			// Check manual ID
-			// id-number is out of valid range
-			if (!is_numeric($this->attributes['uidNumber'][0]) || ($this->attributes['uidNumber'][0] < $minID) || ($this->attributes['uidNumber'][0] > $maxID)) $errors[] = array('ERROR', _('ID-Number'), sprintf(_('Please enter a value between %s and %s!'), $minID, $maxID));
-			// $uids is allways an array but not if no entries were found
-			if (is_array($uids)) {
-				// id-number is in use and account is a new account
-				if ((in_array($this->attributes['uidNumber'][0], $uids)) && $this->orig['uidNumber'][0]=='') $errors[] = array('ERROR', _('ID-Number'), _('ID is already in use'));
-				// id-number is in use, account is existing account and id-number is not used by itself
-				if ((in_array($this->attributes['uidNumber'][0], $uids)) && $this->orig['uidNumber'][0]!='' && ($this->orig['uidNumber'][0] != $this->attributes['uidNumber'][0]) ) {
-					$errors[] = $this->messages['uidNumber'][3];
-					$this->attributes['uidNumber'][0] = $this->orig['uidNumber'][0];
+			// check manual ID
+			if ($this->getAccountContainer()->isNewAccount || !isset($this->orig['uidNumber'][0]) || ($this->orig['uidNumber'][0] != $this->attributes['uidNumber'][0])) {
+				// check range
+				if (!is_numeric($this->attributes['uidNumber'][0]) || ($this->attributes['uidNumber'][0] < $minID) || ($this->attributes['uidNumber'][0] > $maxID)) $errors[] = array('ERROR', _('ID-Number'), sprintf(_('Please enter a value between %s and %s!'), $minID, $maxID));
+				// $uids is always an array but not if no entries were found
+				if (is_array($uids)) {
+					// id-number is in use and account is a new account
+					if ((in_array($this->attributes['uidNumber'][0], $uids)) && $this->orig['uidNumber'][0]=='') $errors[] = array('ERROR', _('ID-Number'), _('ID is already in use'));
+					// id-number is in use, account is existing account and id-number is not used by itself
+					if ((in_array($this->attributes['uidNumber'][0], $uids)) && $this->orig['uidNumber'][0]!='' && ($this->orig['uidNumber'][0] != $this->attributes['uidNumber'][0]) ) {
+						$errors[] = $this->messages['uidNumber'][3];
+						$this->attributes['uidNumber'][0] = $this->orig['uidNumber'][0];
+					}
 				}
 			}
 		}
diff --git a/lam/lib/modules/posixGroup.inc b/lam/lib/modules/posixGroup.inc
index 1214bfd2..ef652352 100644
--- a/lam/lib/modules/posixGroup.inc
+++ b/lam/lib/modules/posixGroup.inc
@@ -568,23 +568,25 @@ class posixGroup extends baseModule {
 			}
 			else {
 				// Check manual ID
-				// id-number is out of valid range
-				if (($this->attributes['gidNumber'][0] < $minID) || ($this->attributes['gidNumber'][0] > $maxID) || !is_numeric($this->attributes['gidNumber'][0])) {
-					$errors[] = array('ERROR', _('ID-Number'), sprintf(_('Please enter a value between %s and %s!'), $minID, $maxID));
-					if (isset($this->orig['gidNumber'][0])) $this->attributes['gidNumber'][0] = $this->orig['gidNumber'][0];
-					else unset($this->attributes['gidNumber'][0]);
-				}
-				// $uids is allways an array but not if no entries were found
-				if (is_array($gids)) {
-					// id-number is in use and account is a new account
-					if ((in_array($this->attributes['gidNumber'][0], $gids)) && $this->orig['gidNumber'][0]=='') {
-						$errors[] = array('ERROR', _('ID-Number'), _('ID is already in use'));
-						unset($this->attributes['gidNumber'][0]);
+				if ($this->getAccountContainer()->isNewAccount || !isset($this->orig['gidNumber'][0]) || ($this->orig['gidNumber'][0] != $this->attributes['gidNumber'][0])) {
+					// check range
+					if (($this->attributes['gidNumber'][0] < $minID) || ($this->attributes['gidNumber'][0] > $maxID) || !is_numeric($this->attributes['gidNumber'][0])) {
+						$errors[] = array('ERROR', _('ID-Number'), sprintf(_('Please enter a value between %s and %s!'), $minID, $maxID));
+						if (isset($this->orig['gidNumber'][0])) $this->attributes['gidNumber'][0] = $this->orig['gidNumber'][0];
+						else unset($this->attributes['gidNumber'][0]);
 					}
-					// id-number is in use, account is existing account and id-number is not used by itself
-					if ((in_array($this->attributes['gidNumber'][0], $gids)) && $this->orig['gidNumber'][0]!='' && ($this->orig['gidNumber'][0] != $this->attributes['gidNumber'][0]) ) {
-						$errors[] = $this->messages['gidNumber'][4];
-						$this->attributes['gidNumber'][0] = $this->orig['gidNumber'][0];
+					// $uids is allways an array but not if no entries were found
+					if (is_array($gids)) {
+						// id-number is in use and account is a new account
+						if ((in_array($this->attributes['gidNumber'][0], $gids)) && $this->orig['gidNumber'][0]=='') {
+							$errors[] = array('ERROR', _('ID-Number'), _('ID is already in use'));
+							unset($this->attributes['gidNumber'][0]);
+						}
+						// id-number is in use, account is existing account and id-number is not used by itself
+						if ((in_array($this->attributes['gidNumber'][0], $gids)) && $this->orig['gidNumber'][0]!='' && ($this->orig['gidNumber'][0] != $this->attributes['gidNumber'][0]) ) {
+							$errors[] = $this->messages['gidNumber'][4];
+							$this->attributes['gidNumber'][0] = $this->orig['gidNumber'][0];
+						}
 					}
 				}
 			}