diff --git a/pages/FileUpload.py b/pages/FileUpload.py
index 2a5443eb..99d62458 100644
--- a/pages/FileUpload.py
+++ b/pages/FileUpload.py
@@ -90,7 +90,8 @@ def handleInputFiles(uploaded_files):
             session_name = 'deconv-mzMLs'
         elif file.name.endswith('_annotated.mzML'):
             session_name = 'anno-mzMLs'
-
+        print(file.name)
+        print(st.session_state[session_name])
         if file.name not in st.session_state[session_name]:
             with open(
                     Path(st.session_state.workspace, session_name, file.name), "wb"
diff --git a/src/Workflow.py b/src/Workflow.py
index 64bfe69a..5a2b4d71 100644
--- a/src/Workflow.py
+++ b/src/Workflow.py
@@ -355,14 +355,18 @@ def pp(self) -> None:
             current_base = splitext(basename(in_mzML))[0]
             current_time = time.strftime("%Y%m%d-%H%M%S")
 
-            out_anno = join(base_path, 'anno-mzMLs', f'{current_base}_{current_time}_annotated.mzML')
-            out_deconv = join(base_path, 'deconv-mzMLs', f'{current_base}_{current_time}_deconv.mzML')
+            out_anno = Path(join(base_path, 'anno-mzMLs', f'{current_base}_{current_time}_annotated.mzML'))
+            out_deconv = Path(join(base_path, 'deconv-mzMLs', f'{current_base}_{current_time}_deconv.mzML'))
 
             uploaded_files.append(out_anno)
             uploaded_files.append(out_deconv)
-
-            st.session_state['deconv-mzMLs'].append(Path(out_deconv).name)
-            st.session_state['anno-mzMLs'].append(Path(out_anno).name)
+            
+            if  'deconv-mzMLs' not in st.session_state:
+                st.session_state['deconv-mzMLs'] = []
+            if  'anno-mzMLs' not in st.session_state:
+                st.session_state['anno-mzMLs'] = []
+            st.session_state['deconv-mzMLs'].append(out_deconv.name)
+            st.session_state['anno-mzMLs'].append(out_anno.name)
 
         # make directory to store deconv and anno mzML files & initialize data storage
         postprocessingAfterUpload_FD(uploaded_files)