diff --git a/lib/spack/spack/compilers/__init__.py b/lib/spack/spack/compilers/__init__.py
index 919380f5f26..e7a7f1d5895 100644
--- a/lib/spack/spack/compilers/__init__.py
+++ b/lib/spack/spack/compilers/__init__.py
@@ -210,8 +210,10 @@ def find_compilers(*path_hints):
 
     # Here we map the function arguments to the corresponding calls
     tp = multiprocessing.pool.ThreadPool()
-    detected_versions = tp.map(detect_version, arguments)
-    tp.close()
+    try:
+        detected_versions = tp.map(detect_version, arguments)
+    finally:
+        tp.close()
 
     def valid_version(item):
         value, error = item