diff --git a/src/scgenerator/spectra.py b/src/scgenerator/spectra.py
index 2ddfe5f..b301189 100644
--- a/src/scgenerator/spectra.py
+++ b/src/scgenerator/spectra.py
@@ -158,6 +158,9 @@ class SimulationSeries:
             raise FileNotFoundError(f"No simulation in {path}")
         self.fibers = [SimulatedFiber(self.path)]
         while (p := self.fibers[-1].params.prev_data_dir) is not None:
+            p = Path(p)
+            if not p.is_absolute():
+                p = Path(self.fibers[-1].params.output_path) / p
             self.fibers.append(SimulatedFiber(p))
         self.fibers = self.fibers[::-1]
 
@@ -353,6 +356,7 @@ class SimulatedFiber:
     def __init__(self, path: os.PathLike):
         self.path = Path(path)
         self.params = Parameters(**translate_parameters(load_toml(self.path / PARAM_FN)))
+        self.params.output_path = str(self.path.resolve())
         self.t = self.params.t
         self.w = self.params.w
         self.z = self.params.z_targets
diff --git a/src/scgenerator/utils.py b/src/scgenerator/utils.py
index 0cb5951..0b3067e 100644
--- a/src/scgenerator/utils.py
+++ b/src/scgenerator/utils.py
@@ -21,7 +21,7 @@ import pkg_resources as pkg
 import tomli
 import tomli_w
 
-from .const import PARAM_FN, PARAM_SEPARATOR, SPEC1_FN, SPECN_FN1, Z_FN, ROOT_PARAMETERS
+from .const import PARAM_FN, PARAM_SEPARATOR, SPEC1_FN, Z_FN, ROOT_PARAMETERS
 from .logger import get_logger
 from .errors import DuplicateParameterError
 
@@ -489,7 +489,7 @@ def update_params(new_path: Path, file: Path):
     params = load_toml(file)
     if (p := params.get("prev_data_dir")) is not None:
         p = Path(p)
-        params["prev_data_dir"] = str(p.parent / update_path_name(p.name))
+        params["prev_data_dir"] = str(Path("../..") / p.parent.name / update_path_name(p.name))
     params["output_path"] = str(new_path)
     save_toml(new_path / PARAM_FN, params)
     file.unlink()