diff --git a/README.md b/README.md
index df44970..af23868 100644
--- a/README.md
+++ b/README.md
@@ -1,3 +1,16 @@
 # ubuntu
 
-Issues related to Ubuntu OS or related distributions
\ No newline at end of file
+Issues related to Ubuntu OS or related distributions
+
+## apt errors
+If you want to delete an wrong or non-working repository you can listed and delete by going to:
+
+```
+$ cd /etc/apt/sources.list.d
+$ ls 
+docker.list  elementary.list  owncloud.list  patches.list
+```
+
+and you can remove with `rm` commad, in my case I added by error the owncloud repository, thus, I have to remove it:
+
+