diff --git a/config.toml.example b/config.toml.example
index 39c94d41e3a..9135843045a 100644
--- a/config.toml.example
+++ b/config.toml.example
@@ -393,6 +393,7 @@
 #incremental = false
 
 # Build a multi-threaded rustc
+# FIXME(#75760): Some UI tests fail when this option is enabled.
 #parallel-compiler = false
 
 # The default linker that will be hard-coded into the generated compiler for