diff --git a/frameworks/RandomForest/__init__.py b/frameworks/RandomForest/__init__.py
index b024b051c..a25cbeee7 100644
--- a/frameworks/RandomForest/__init__.py
+++ b/frameworks/RandomForest/__init__.py
@@ -1,6 +1,6 @@
 from amlb.benchmark import TaskConfig
 from amlb.data import Dataset
-from amlb.utils import call_script_in_same_dir
+from amlb.utils import call_script_in_same_dir, unsparsify
 
 
 def setup(*args, **kwargs):
@@ -14,6 +14,7 @@ def run(dataset: Dataset, config: TaskConfig):
     encode = config.framework_params.get('_encode', True)
     X_train, X_test = impute_array(dataset.train.X_enc, dataset.test.X_enc) if encode else (dataset.train.X, dataset.test.X)
     y_train, y_test = (dataset.train.y_enc, dataset.test.y_enc) if encode else (dataset.train.y, dataset.test.y)
+    y_train, y_test = unsparsify(y_train, y_test)
     data = dict(
         train=dict(
             X=X_train,
diff --git a/frameworks/TunedRandomForest/__init__.py b/frameworks/TunedRandomForest/__init__.py
index a98dfdfac..561678497 100644
--- a/frameworks/TunedRandomForest/__init__.py
+++ b/frameworks/TunedRandomForest/__init__.py
@@ -1,6 +1,6 @@
 from amlb.benchmark import TaskConfig
 from amlb.data import Dataset
-from amlb.utils import call_script_in_same_dir
+from amlb.utils import call_script_in_same_dir, unsparsify
 
 
 def setup(*args, **kwargs):
@@ -12,7 +12,7 @@ def run(dataset: Dataset, config: TaskConfig):
     from frameworks.shared.caller import run_in_venv
 
     X_train, X_test = impute_array(dataset.train.X_enc, dataset.test.X_enc)
-    y_train, y_test = (dataset.train.y_enc, dataset.test.y_enc)
+    y_train, y_test = unsparsify(dataset.train.y_enc, dataset.test.y_enc)
     data = dict(
         train=dict(
             X=X_train,
diff --git a/frameworks/shared/caller.py b/frameworks/shared/caller.py
index ee60b42d4..b4c9b0210 100644
--- a/frameworks/shared/caller.py
+++ b/frameworks/shared/caller.py
@@ -93,7 +93,7 @@ def run_in_venv(caller_file, script_file: str, *args,
     ser_config = options['serialization']
     env = options['env'] or ns()
 
-    with TemporaryDirectory() as tmpdir:
+    with TemporaryDirectory(prefix='amlb_', suffix='_xproc') as tmpdir:
 
         ds = _make_input_dataset(input_data, dataset, tmpdir, serialization=ser_config)