diff --git a/apps/files_sharing/lib/Controller/ShareesAPIController.php b/apps/files_sharing/lib/Controller/ShareesAPIController.php
index 0e94cfb9d7c94..0a7e25b2cce5b 100644
--- a/apps/files_sharing/lib/Controller/ShareesAPIController.php
+++ b/apps/files_sharing/lib/Controller/ShareesAPIController.php
@@ -610,32 +610,35 @@ protected function getEmail($search) {
 					$exactEmailMatch = strtolower($emailAddress) === $lowerSearch;
 
 					if (isset($contact['isLocalSystemBook'])) {
-						if ($exactEmailMatch) {
-							$cloud = $this->cloudIdManager->resolveCloudId($contact['CLOUD'][0]);
-							if (!$this->hasUserInResult($cloud->getUser())) {
-								$this->result['exact']['users'][] = [
-									'label' => $contact['FN'] . " ($emailAddress)",
-									'value' => [
-										'shareType' => Share::SHARE_TYPE_USER,
-										'shareWith' => $cloud->getUser(),
-									],
-								];
+						// check whether CLOUD ends with @, which is probably a leftover from an earlier version of OwnCloud
+						if (!((strlen($contact['CLOUD'][0]) > 0) && (substr_compare($contact['CLOUD'][0], "@", strlen($contact['CLOUD'][0])-strlen("@"), strlen("@")) === 0))) {
+							if ($exactEmailMatch) {
+								$cloud = $this->cloudIdManager->resolveCloudId($contact['CLOUD'][0]);
+								if (!$this->hasUserInResult($cloud->getUser())) {
+									$this->result['exact']['users'][] = [
+										'label' => $contact['FN'] . " ($emailAddress)",
+										'value' => [
+											'shareType' => Share::SHARE_TYPE_USER,
+											'shareWith' => $cloud->getUser(),
+										],
+									];
+								}
+								return ['results' => [], 'exact' => [], 'exactIdMatch' => true];
 							}
-							return ['results' => [], 'exact' => [], 'exactIdMatch' => true];
-						}
-						if ($this->shareeEnumeration) {
-							$cloud = $this->cloudIdManager->resolveCloudId($contact['CLOUD'][0]);
-							if (!$this->hasUserInResult($cloud->getUser())) {
-								$this->result['users'][] = [
-									'label' => $contact['FN'] . " ($emailAddress)",
-									'value' => [
-										'shareType' => Share::SHARE_TYPE_USER,
-										'shareWith' => $cloud->getUser(),
-									],
-								];
+							if ($this->shareeEnumeration) {
+								$cloud = $this->cloudIdManager->resolveCloudId($contact['CLOUD'][0]);
+								if (!$this->hasUserInResult($cloud->getUser())) {
+									$this->result['users'][] = [
+										'label' => $contact['FN'] . " ($emailAddress)",
+										'value' => [
+											'shareType' => Share::SHARE_TYPE_USER,
+											'shareWith' => $cloud->getUser(),
+										],
+									];
+								}
 							}
+							continue;
 						}
-						continue;
 					}
 
 					if ($exactEmailMatch || strtolower($contact['FN']) === $lowerSearch) {