diff --git a/solr/contrib/clustering/DISABLED-README.txt b/solr/contrib/clustering/DISABLED-README.txt
new file mode 100644
index 00000000000..8a43dbda63d
--- /dev/null
+++ b/solr/contrib/clustering/DISABLED-README.txt
@@ -0,0 +1,7 @@
+In trunk this contrib module is currently disabled, as it uses the external
+(binary) Carrot2 library (as trunk is free to change its API, this module fails
+with linking exceptions).
+
+After a stable branch of Lucene is created from trunk, rename
+'build.xml.disabled' back to 'build.xml' after replacing the Carrot2
+JARs by updated versions.
diff --git a/solr/contrib/clustering/build.xml b/solr/contrib/clustering/build.xml.disabled
similarity index 100%
rename from solr/contrib/clustering/build.xml
rename to solr/contrib/clustering/build.xml.disabled