diff --git a/code/Common/ScenePreprocessor.cpp b/code/Common/ScenePreprocessor.cpp
index 432a3d766..a47053de4 100644
--- a/code/Common/ScenePreprocessor.cpp
+++ b/code/Common/ScenePreprocessor.cpp
@@ -217,6 +217,7 @@ void ScenePreprocessor::ProcessAnimation (aiAnimation* anim)
 
                 // No rotation keys? Generate a dummy track
                 if (!channel->mNumRotationKeys) {
+                    ai_assert(!channel->mRotationKeys);
                     channel->mNumRotationKeys = 1;
                     channel->mRotationKeys = new aiQuatKey[1];
                     aiQuatKey& q = channel->mRotationKeys[0];
@@ -225,10 +226,13 @@ void ScenePreprocessor::ProcessAnimation (aiAnimation* anim)
                     q.mValue = rotation;
 
                     ASSIMP_LOG_DEBUG("ScenePreprocessor: Dummy rotation track has been generated");
+                } else {
+                    ai_assert(channel->mRotationKeys);
                 }
 
                 // No scaling keys? Generate a dummy track
                 if (!channel->mNumScalingKeys)  {
+                    ai_assert(!channel->mScalingKeys);
                     channel->mNumScalingKeys = 1;
                     channel->mScalingKeys = new aiVectorKey[1];
                     aiVectorKey& q = channel->mScalingKeys[0];
@@ -237,10 +241,13 @@ void ScenePreprocessor::ProcessAnimation (aiAnimation* anim)
                     q.mValue = scaling;
 
                     ASSIMP_LOG_DEBUG("ScenePreprocessor: Dummy scaling track has been generated");
+                } else {
+                    ai_assert(channel->mScalingKeys);
                 }
 
                 // No position keys? Generate a dummy track
                 if (!channel->mNumPositionKeys) {
+                    ai_assert(!channel->mPositionKeys);
                     channel->mNumPositionKeys = 1;
                     channel->mPositionKeys = new aiVectorKey[1];
                     aiVectorKey& q = channel->mPositionKeys[0];
@@ -249,6 +256,8 @@ void ScenePreprocessor::ProcessAnimation (aiAnimation* anim)
                     q.mValue = position;
 
                     ASSIMP_LOG_DEBUG("ScenePreprocessor: Dummy position track has been generated");
+                } else {
+                    ai_assert(channel->mPositionKeys);
                 }
             }
         }
diff --git a/code/X/XFileImporter.cpp b/code/X/XFileImporter.cpp
index 122033b08..70c6869b3 100644
--- a/code/X/XFileImporter.cpp
+++ b/code/X/XFileImporter.cpp
@@ -513,30 +513,36 @@ void XFileImporter::CreateAnimations( aiScene* pScene, const XFile::Scene* pData
             } else {
                 // separate key sequences for position, rotation, scaling
                 nbone->mNumPositionKeys = (unsigned int)bone->mPosKeys.size();
-                nbone->mPositionKeys = new aiVectorKey[nbone->mNumPositionKeys];
-                for( unsigned int c = 0; c < nbone->mNumPositionKeys; ++c ) {
-                    aiVector3D pos = bone->mPosKeys[c].mValue;
+                if (nbone->mNumPositionKeys != 0) {
+                    nbone->mPositionKeys = new aiVectorKey[nbone->mNumPositionKeys];
+                    for( unsigned int c = 0; c < nbone->mNumPositionKeys; ++c ) {
+                        aiVector3D pos = bone->mPosKeys[c].mValue;
 
-                    nbone->mPositionKeys[c].mTime = bone->mPosKeys[c].mTime;
-                    nbone->mPositionKeys[c].mValue = pos;
+                        nbone->mPositionKeys[c].mTime = bone->mPosKeys[c].mTime;
+                        nbone->mPositionKeys[c].mValue = pos;
+                    }
                 }
 
                 // rotation
                 nbone->mNumRotationKeys = (unsigned int)bone->mRotKeys.size();
-                nbone->mRotationKeys = new aiQuatKey[nbone->mNumRotationKeys];
-                for( unsigned int c = 0; c < nbone->mNumRotationKeys; ++c ) {
-                    aiMatrix3x3 rotmat = bone->mRotKeys[c].mValue.GetMatrix();
+                if (nbone->mNumRotationKeys != 0) {
+                    nbone->mRotationKeys = new aiQuatKey[nbone->mNumRotationKeys];
+                    for( unsigned int c = 0; c < nbone->mNumRotationKeys; ++c ) {
+                        aiMatrix3x3 rotmat = bone->mRotKeys[c].mValue.GetMatrix();
 
-                    nbone->mRotationKeys[c].mTime = bone->mRotKeys[c].mTime;
-                    nbone->mRotationKeys[c].mValue = aiQuaternion( rotmat);
-                    nbone->mRotationKeys[c].mValue.w *= -1.0f; // needs quat inversion
+                        nbone->mRotationKeys[c].mTime = bone->mRotKeys[c].mTime;
+                        nbone->mRotationKeys[c].mValue = aiQuaternion( rotmat);
+                        nbone->mRotationKeys[c].mValue.w *= -1.0f; // needs quat inversion
+                    }
                 }
 
                 // scaling
                 nbone->mNumScalingKeys = (unsigned int)bone->mScaleKeys.size();
-                nbone->mScalingKeys = new aiVectorKey[nbone->mNumScalingKeys];
-                for( unsigned int c = 0; c < nbone->mNumScalingKeys; c++)
-                    nbone->mScalingKeys[c] = bone->mScaleKeys[c];
+                if (nbone->mNumScalingKeys != 0) {
+                    nbone->mScalingKeys = new aiVectorKey[nbone->mNumScalingKeys];
+                    for( unsigned int c = 0; c < nbone->mNumScalingKeys; c++)
+                        nbone->mScalingKeys[c] = bone->mScaleKeys[c];
+                }
 
                 // longest lasting key sequence determines duration
                 if( bone->mPosKeys.size() > 0)
diff --git a/test/unit/utXImporterExporter.cpp b/test/unit/utXImporterExporter.cpp
index 15e19cf01..2c6830978 100644
--- a/test/unit/utXImporterExporter.cpp
+++ b/test/unit/utXImporterExporter.cpp
@@ -132,15 +132,8 @@ TEST(utXImporter, TestFormatDetection) {
 }
 
 
-#if 0  // FIXME: disabled because it leaks memory
-
-
 TEST(utXImporter, importDwarf) {
     Assimp::Importer importer;
     const aiScene *scene = importer.ReadFile(ASSIMP_TEST_MODELS_NONBSD_DIR "/X/dwarf.x", aiProcess_ValidateDataStructure);
     ASSERT_NE(nullptr, scene);
 }
-
-
-#endif  // 0
-