diff --git a/src/plugins/qt4projectmanager/qt-desktop/qt4desktoptargetfactory.cpp b/src/plugins/qt4projectmanager/qt-desktop/qt4desktoptargetfactory.cpp
index 681ccfee86b85a08cf5c2c61191f96d532ca698f..ee6190e93ca8eedc7d1db72d6ea55297d766351c 100644
--- a/src/plugins/qt4projectmanager/qt-desktop/qt4desktoptargetfactory.cpp
+++ b/src/plugins/qt4projectmanager/qt-desktop/qt4desktoptargetfactory.cpp
@@ -121,6 +121,8 @@ QList<BuildConfigurationInfo> Qt4DesktopTargetFactory::availableBuildConfigurati
     QList<QtVersion *> knownVersions = QtVersionManager::instance()->versionsForTargetId(Constants::DESKTOP_TARGET_ID);
 
     foreach (QtVersion *version, knownVersions) {
+        if (!version->isValid())
+            continue;
         bool buildAll = version->defaultBuildConfig() & QtVersion::BuildAll;
         QtVersion::QmakeBuildConfigs config = buildAll ? QtVersion::BuildAll : QtVersion::QmakeBuildConfig(0);
 
diff --git a/src/plugins/qt4projectmanager/qt-desktop/qt4simulatortargetfactory.cpp b/src/plugins/qt4projectmanager/qt-desktop/qt4simulatortargetfactory.cpp
index 0ce2888dca5d2f1394782d1e73d7c2bc191e0fa8..7c94d026c1fb072133946f8f1b00aab9b9bc638b 100644
--- a/src/plugins/qt4projectmanager/qt-desktop/qt4simulatortargetfactory.cpp
+++ b/src/plugins/qt4projectmanager/qt-desktop/qt4simulatortargetfactory.cpp
@@ -123,6 +123,8 @@ QList<BuildConfigurationInfo> Qt4SimulatorTargetFactory::availableBuildConfigura
     QList<QtVersion *> knownVersions = QtVersionManager::instance()->versionsForTargetId(Constants::QT_SIMULATOR_TARGET_ID);
 
     foreach (QtVersion *version, knownVersions) {
+        if (!version->isValid())
+            continue;
         bool buildAll = version->defaultBuildConfig() & QtVersion::BuildAll;
         QtVersion::QmakeBuildConfigs config = buildAll ? QtVersion::BuildAll : QtVersion::QmakeBuildConfig(0);
         QString dir = defaultShadowBuildDirectory(Qt4Project::defaultTopLevelBuildDirectory(proFilePath), Constants::QT_SIMULATOR_TARGET_ID);
diff --git a/src/plugins/qt4projectmanager/qt-maemo/qt4maemotargetfactory.cpp b/src/plugins/qt4projectmanager/qt-maemo/qt4maemotargetfactory.cpp
index 88dde69b8221073291e44f34a397feb7fcd0417a..34d566934a0323345a7b226a9acbca5aa2ae7273 100644
--- a/src/plugins/qt4projectmanager/qt-maemo/qt4maemotargetfactory.cpp
+++ b/src/plugins/qt4projectmanager/qt-maemo/qt4maemotargetfactory.cpp
@@ -147,6 +147,8 @@ QList<BuildConfigurationInfo> Qt4MaemoTargetFactory::availableBuildConfiguration
     QList<QtVersion *> knownVersions = QtVersionManager::instance()->versionsForTargetId(id);
 
     foreach (QtVersion *version, knownVersions) {
+        if (!version->isValid())
+            continue;
         bool buildAll = version->defaultBuildConfig() & QtVersion::BuildAll;
         QtVersion::QmakeBuildConfigs config = buildAll ? QtVersion::BuildAll : QtVersion::QmakeBuildConfig(0);
         QString dir = defaultShadowBuildDirectory(Qt4Project::defaultTopLevelBuildDirectory(proFilePath), id);
diff --git a/src/plugins/qt4projectmanager/qt-s60/qt4symbiantargetfactory.cpp b/src/plugins/qt4projectmanager/qt-s60/qt4symbiantargetfactory.cpp
index 901a0ec70b498d2af4f6f4a956a8c411f146666b..1a3ad9c6ef244f71a3fd691f5df0f54483927d2c 100644
--- a/src/plugins/qt4projectmanager/qt-s60/qt4symbiantargetfactory.cpp
+++ b/src/plugins/qt4projectmanager/qt-s60/qt4symbiantargetfactory.cpp
@@ -132,6 +132,8 @@ QList<BuildConfigurationInfo> Qt4SymbianTargetFactory::availableBuildConfigurati
     QList<QtVersion *> knownVersions = QtVersionManager::instance()->versionsForTargetId(Constants::S60_EMULATOR_TARGET_ID);
 
     foreach (QtVersion *version, knownVersions) {
+        if (!version->isValid())
+            continue;
         bool buildAll = version->defaultBuildConfig() & QtVersion::BuildAll;
         QtVersion::QmakeBuildConfigs config = buildAll ? QtVersion::BuildAll : QtVersion::QmakeBuildConfig(0);
         QString dir = defaultShadowBuildDirectory(Qt4Project::defaultTopLevelBuildDirectory(proFilePath), Constants::S60_EMULATOR_TARGET_ID);
@@ -140,6 +142,8 @@ QList<BuildConfigurationInfo> Qt4SymbianTargetFactory::availableBuildConfigurati
 
     knownVersions = QtVersionManager::instance()->versionsForTargetId(Constants::S60_DEVICE_TARGET_ID);
     foreach (QtVersion *version, knownVersions) {
+        if (!version->isValid())
+            continue;
         bool buildAll = version->defaultBuildConfig() & QtVersion::BuildAll;
         QtVersion::QmakeBuildConfigs config = buildAll ? QtVersion::BuildAll : QtVersion::QmakeBuildConfig(0);
         QString dir = defaultShadowBuildDirectory(Qt4Project::defaultTopLevelBuildDirectory(proFilePath), Constants::S60_DEVICE_TARGET_ID);