diff --git a/simpeg_drivers-assets/uijson/plate_sweep.ui.json b/simpeg_drivers-assets/uijson/plate_sweep.ui.json
index 822e2988..8a1853b7 100644
--- a/simpeg_drivers-assets/uijson/plate_sweep.ui.json
+++ b/simpeg_drivers-assets/uijson/plate_sweep.ui.json
@@ -24,16 +24,12 @@
     "workdir": {
         "main": true,
         "group": "Base",
-        "label": "Working directory",
-        "fileDescription": [
-            "Directory"
-        ],
-        "fileType": [
-            "directory"
-        ],
+        "label": "Output directory",
         "directoryOnly": true,
-        "enabled": true,
-        "value": ""
+        "enabled": false,
+        "optional": true,
+        "tootip": "Directory to store simulation results, relative to the working geoh5.",
+        "value": "./simulations"
     },
     "background_start": {
         "main": true,
diff --git a/simpeg_drivers/components/factories/misfit_factory.py b/simpeg_drivers/components/factories/misfit_factory.py
index 02a7d988..0b7c8d59 100644
--- a/simpeg_drivers/components/factories/misfit_factory.py
+++ b/simpeg_drivers/components/factories/misfit_factory.py
@@ -59,7 +59,9 @@ def assemble_arguments(  # pylint: disable=arguments-differ
         use_futures = self.client
 
         # Pickle the simulation to the temporary file
-        with open(self.params.workpath / "simulation.pkl", mode="wb") as temp_file:
+        with open(
+            self.params.workpath / (self.params.geoh5.h5file.stem + ".pkl"), mode="wb"
+        ) as temp_file:
             pickle.dump(self.simulation, temp_file)
 
         misfits = []
diff --git a/simpeg_drivers/plate_simulation/sweep/driver.py b/simpeg_drivers/plate_simulation/sweep/driver.py
index 2ebfab71..4cfb64fa 100644
--- a/simpeg_drivers/plate_simulation/sweep/driver.py
+++ b/simpeg_drivers/plate_simulation/sweep/driver.py
@@ -146,7 +146,7 @@ def run(self):
 
     @staticmethod
     def run_trial(
-        data: dict, h5file: Path, workdir: Path | None, worker: tuple[str] | None = None
+        data: dict, h5file: Path, workdir: str, worker: tuple[str] | None = None
     ):
         """
         Run a single trial of the plate simulation with name encoding from the parameters.
@@ -159,10 +159,12 @@ def run_trial(
         json_string = dict_to_json_str(data)
         uid = uuid_from_values(json_string)
 
-        if workdir is None:
-            workdir = h5file.parent
+        workerdir = h5file.parent / workdir
 
-        workerfile = workdir / f"{uid}.geoh5"
+        if not workerdir.exists():
+            workerdir.mkdir(exist_ok=True)
+
+        workerfile = workerdir / f"{uid}.geoh5"
         if workerfile.exists():
             logger.info("Skipping trial %s, since the file already exists.", uid)
             return
@@ -197,7 +199,7 @@ def run_trial(
 def run_block(
     trials: list[dict],
     h5file: Path,
-    workdir: Path | None,
+    workdir: str,
     worker: tuple[str] | None = None,
 ):
     """
diff --git a/simpeg_drivers/plate_simulation/sweep/options.py b/simpeg_drivers/plate_simulation/sweep/options.py
index 3c9f6a78..112302ef 100644
--- a/simpeg_drivers/plate_simulation/sweep/options.py
+++ b/simpeg_drivers/plate_simulation/sweep/options.py
@@ -64,7 +64,7 @@ class SweepOptions(Options):
     inversion_type: str = "plate sweep"
     template: SimPEGGroup | UIJsonGroup
     sweeps: list[ParamSweep]
-    workdir: Path | None = None
+    workdir: str = "./simulations"
 
     @field_serializer("sweeps")
     def sweeps_to_params(self, sweeps):
@@ -105,16 +105,7 @@ def collect_sweep(param: str) -> dict:
             }
 
         sweep_params = [k.removesuffix("_start") for k in options if "_start" in k]
-
         options["sweeps"] = [collect_sweep(param) for param in sweep_params]
-        workdir = options["workdir"]
-        if isinstance(workdir, str):
-            options["workdir"] = Path(workdir)
-        if isinstance(workdir, list):
-            if len(workdir) == 0:
-                options["workdir"] = None
-            else:
-                options["workdir"] = Path(workdir[0])
 
         return options
 
diff --git a/simpeg_drivers/plate_simulation/sweep/uijson.py b/simpeg_drivers/plate_simulation/sweep/uijson.py
index 8152f13f..a9a3e866 100644
--- a/simpeg_drivers/plate_simulation/sweep/uijson.py
+++ b/simpeg_drivers/plate_simulation/sweep/uijson.py
@@ -8,9 +8,7 @@
 #                                                                                   '
 # '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
 
-from geoh5py import Workspace
-from geoh5py.shared.utils import fetch_active_workspace
-from geoh5py.ui_json.forms import FileForm, FloatForm, GroupForm, IntegerForm
+from geoh5py.ui_json.forms import FloatForm, GroupForm, IntegerForm, StringForm
 from geoh5py.ui_json.ui_json import BaseUIJson
 from pydantic import ConfigDict
 
@@ -44,4 +42,4 @@ class PlateSweepUIJson(BaseUIJson):
     dip_stop: FloatForm
     dip_count: IntegerForm
     out_group: GroupForm | None
-    workdir: FileForm | None
+    workdir: StringForm | None