diff --git a/gtsam/geometry/SO4.cpp b/gtsam/geometry/SO4.cpp
index 93fb05386..dd15807c3 100644
--- a/gtsam/geometry/SO4.cpp
+++ b/gtsam/geometry/SO4.cpp
@@ -138,7 +138,7 @@ static SO4::VectorN2 vec4(const Matrix4& Q) {
 }
 
 // so<4> generators
-static std::vector<Matrix4> G4(
+static std::vector<Matrix4, Eigen::aligned_allocator<Matrix4> > G4(
     {SO4::Hat(Vector6::Unit(0)), SO4::Hat(Vector6::Unit(1)),
      SO4::Hat(Vector6::Unit(2)), SO4::Hat(Vector6::Unit(3)),
      SO4::Hat(Vector6::Unit(4)), SO4::Hat(Vector6::Unit(5))});