diff --git a/thunderbird.spec b/thunderbird.spec
index 21df563..1004e62 100644
--- a/thunderbird.spec
+++ b/thunderbird.spec
@@ -875,9 +875,9 @@ ls %{_buildrootdir}
 export MACH_USE_SYSTEM_PYTHON=1
 %if 0%{?use_llvmts}
   #scl enable llvm-toolset-%{llvm_version} './mach build -v'
-  ./mach build -v
+  ./mach build -v || exit 1
 %else
-  ./mach build -v
+  ./mach build -v || exit 1
 %endif
 # Look for the reason we get: /usr/lib/rpm/debugedit: canonicalization unexpectedly shrank by one character
 readelf -wl objdir/dist/bin/libxul.so | grep "/"