diff --git a/apps/files_external/lib/Lib/Backend/SMB.php b/apps/files_external/lib/Lib/Backend/SMB.php
index 7cb692ad9a43597923e8da0bc25084b3d346e9cc..5344bf5f78c20860a978d3e10c5175af05209921 100644
--- a/apps/files_external/lib/Lib/Backend/SMB.php
+++ b/apps/files_external/lib/Lib/Backend/SMB.php
@@ -58,7 +58,8 @@ class SMB extends Backend {
 					->setFlag(DefinitionParameter::FLAG_OPTIONAL),
 				(new DefinitionParameter('check_acl', $l->t('Verify ACL access when listing files')))
 					->setType(DefinitionParameter::VALUE_BOOLEAN)
-					->setFlag(DefinitionParameter::FLAG_OPTIONAL),
+					->setFlag(DefinitionParameter::FLAG_OPTIONAL)
+					->setTooltip($l->t("Check the ACL's of each file or folder inside a directory to filter out items where the user has no read permissions, comes with a performance penalty")),
 				(new DefinitionParameter('timeout', $l->t('Timeout')))
 					->setType(DefinitionParameter::VALUE_HIDDEN)
 					->setFlag(DefinitionParameter::FLAG_OPTIONAL),