diff --git a/qmake/generators/mac/pbuilder_pbx.cpp b/qmake/generators/mac/pbuilder_pbx.cpp
index 70efff0bcd..770a1ad34e 100644
--- a/qmake/generators/mac/pbuilder_pbx.cpp
+++ b/qmake/generators/mac/pbuilder_pbx.cpp
@@ -178,7 +178,6 @@ ProjectBuilderMakefileGenerator::writeSubDirs(QTextStream &t)
                     }
                     if(tmp_proj.first("TEMPLATE") == "subdirs") {
                         QMakeProject *pp = new QMakeProject(&tmp_proj);
-                        pp->read(0);
                         pb_subdirs += new ProjectBuilderSubDirs(pp, dir);
                     } else if(tmp_proj.first("TEMPLATE") == "app" || tmp_proj.first("TEMPLATE") == "lib") {
                         QString pbxproj = qmake_getpwd() + Option::dir_sep + tmp_proj.first("TARGET") + projectSuffix();
diff --git a/qmake/project.cpp b/qmake/project.cpp
index ecd31d5234..7f73b1f56f 100644
--- a/qmake/project.cpp
+++ b/qmake/project.cpp
@@ -627,10 +627,11 @@ QMakeProject::init(QMakeProperty *p)
     reset();
 }
 
-QMakeProject::QMakeProject(QMakeProject *p, const QHash<QString, QStringList> *vars)
+// Duplicate project. It is *not* allowed to call the complex read() functions on the copy.
+QMakeProject::QMakeProject(QMakeProject *p, const QHash<QString, QStringList> *_vars)
 {
     init(p->properties());
-    base_vars = vars ? *vars : p->variables();
+    vars = _vars ? *_vars : p->variables();
     for(QHash<QString, FunctionBlock*>::iterator it = p->replaceFunctions.begin(); it != p->replaceFunctions.end(); ++it) {
         it.value()->ref();
         replaceFunctions.insert(it.key(), it.value());