diff --git a/Error-messages.md b/Error-messages.md
index 74968fc..14f03b9 100644
--- a/Error-messages.md
+++ b/Error-messages.md
@@ -11,8 +11,9 @@
 * Third party application is blocking KCC temporary files in some way.
 
 ### Source directory is empty
-* Selected directory don't contain any image files. You cannot have individual chapters in archives.
-  * You cannot use the 'directory' feature with e.g. CBR files. Add them manually by multi-selection via "Add File"
+* Selected directory don't contain any image files. You cannot have individual chapters in archives. 
+  * You cannot use the 'directory' feature with e.g. CBR files. Add them manually by multi-selection via "Add File(s)"
+  * If you want to merge chapters into 1 file, extract all the folders first like in: https://github.com/ciromattia/kcc/issues/612#issuecomment-2117985011
 
 ### Failed to extract images from PDF file
 * PDF file has too complex structure.