diff --git a/.package-lists/guix-emacs-manifest.scm b/.package-lists/guix-emacs-manifest.scm
index 6c04ade6..b3fbade9 100644
--- a/.package-lists/guix-emacs-manifest.scm
+++ b/.package-lists/guix-emacs-manifest.scm
@@ -99,7 +99,7 @@
     "emacs-sx"
     "emacs-synosaurus"
     "emacs-transmission"
-    "emacs-undo-tree"
+    ;; "emacs-undo-tree" ; TODO: Too broken.
     "emacs-unfill"
     "emacs-w3m"
     "emacs-wgrep"