diff --git a/Cask b/Cask
index c224206..e040aaa 100644
--- a/Cask
+++ b/Cask
@@ -1,5 +1,5 @@
 (source gnu)
-(source melpa-stable)
+(source melpa)
 
 (depends-on "buttercup")
 (depends-on "pdf-tools")
diff --git a/org-noter-core.el b/org-noter-core.el
index a945131..629eccf 100644
--- a/org-noter-core.el
+++ b/org-noter-core.el
@@ -1778,7 +1778,8 @@ can still be initiated from the notes file, but not vice-versa,
 nor will future renames of the document be synced in the notes
 file."
 
-  (when (and (member-ignore-case (file-name-extension document-path)
+  (when (and (file-name-extension document-path)
+             (member-ignore-case (file-name-extension document-path)
                                  org-noter--doc-extensions)
              (not (file-exists-p document-path))
              (file-exists-p new-document-path))