diff --git a/conda_build/config.py b/conda_build/config.py
index 8700a65a7a..733008d5e6 100644
--- a/conda_build/config.py
+++ b/conda_build/config.py
@@ -58,7 +58,7 @@ def get_conda_py(self):
         croot = abspath(expanduser('~/conda-bld'))
 
     short_build_prefix = join(cc.envs_dirs[0], '_build')
-    long_build_prefix = max(short_build_prefix, (short_build_prefix + 8 * '_placehold')[:128])
+    long_build_prefix = max(short_build_prefix, (short_build_prefix + 8 * '_placehold')[:80])
     # XXX: Make this None to be more rigorous about requiring the build_prefix
     # to be known before it is used.
     use_long_build_prefix = False