diff --git a/src/tufup/repo/__init__.py b/src/tufup/repo/__init__.py
index f75a5f8..6eef251 100644
--- a/src/tufup/repo/__init__.py
+++ b/src/tufup/repo/__init__.py
@@ -594,8 +594,9 @@ def save_config(self):
         """Save current configuration."""
         config_file_path = self.get_config_file_path()
         # make paths relative to current working directory (cwd),
-        # if possible, otherwise keep absolute paths (note, to avoid
-        # confusion, using paths other than cwd is discouraged)
+        # if possible, otherwise keep absolute paths (see #50)
+        # (note, to avoid confusion, using paths other than cwd is discouraged)
+        # also enforce posix paths on windows (see #147)
         temp_config_dict = self.config_dict  # note self.config_dict is a property
         for key in ['repo_dir', 'keys_dir']:
             try:
@@ -605,13 +606,14 @@ def save_config(self):
                     # which are truncated with a tilde,
                     # e.g. c:\Users\RUNNER~1\...
                     pathlib.Path.cwd().resolve()
-                )
+                ).as_posix()
             except ValueError:
                 logger.warning(
                     f'Saving *absolute* path to config, because the path'
                     f' ({temp_config_dict[key]}) is not relative to cwd'
                     f' ({pathlib.Path.cwd()})'
                 )
+                temp_config_dict[key] = temp_config_dict[key].as_posix()
         # write file
         config_file_path.write_text(
             data=json.dumps(temp_config_dict, default=str, sort_keys=True, indent=4),
@@ -629,6 +631,12 @@ def load_config(cls) -> dict:
             logger.warning(f'config file not found: {file_path}')
         except json.JSONDecodeError:
             logger.warning(f'config file invalid: {file_path}')
+        # enforce posix paths (for legacy windows configs loaded on linux, see #147)
+        for key in ['repo_dir', 'keys_dir']:
+            value = config_dict.get(key)
+            if value:
+                # interpret the value as a windows path (\\ or /) then enforce posix (/)
+                config_dict[key] = pathlib.PureWindowsPath(value).as_posix()
         return config_dict
 
     @classmethod
diff --git a/tests/test_repo.py b/tests/test_repo.py
index e3dfce3..88fde46 100644
--- a/tests/test_repo.py
+++ b/tests/test_repo.py
@@ -1,5 +1,6 @@
 import copy
 import tarfile
+import unittest
 from datetime import date, datetime, timedelta
 import json
 import logging
@@ -37,7 +38,7 @@
     SUFFIX_PUB,
     SUFFIX_PATCH,
 )
-
+from tufup.utils.platform_specific import ON_WINDOWS
 
 mock_input = Mock(return_value='')
 
@@ -545,6 +546,21 @@ def test_save_config(self):
                 # note Path.is_relative_to() is introduced in python 3.9
                 self.assertFalse(pathlib.Path(config_dict[key]).is_absolute())
 
+    @unittest.skipUnless(condition=ON_WINDOWS, reason='windows only')
+    def test_save_config_windows_paths(self):
+        # prepare
+        kwargs = dict(repo_dir='foo\\repo', keys_dir='bar\\keys')
+        repo = Repository(app_name='test', **kwargs)
+        # test
+        repo.save_config()
+        self.assertTrue(repo.get_config_file_path().exists())
+        config_text = repo.get_config_file_path().read_text()
+        print(config_text)
+        config = json.loads(repo.get_config_file_path().read_text())
+        for key in kwargs.keys():
+            with self.subTest(msg=key):
+                self.assertEqual(kwargs[key].replace('\\', '/'), config[key])
+
     def test_load_config(self):
         # file does not exist
         self.assertEqual(dict(), Repository.load_config())
@@ -553,6 +569,19 @@ def test_load_config(self):
         # test
         self.assertEqual(dict(), Repository.load_config())
 
+    @unittest.skipIf(condition=ON_WINDOWS, reason='posix only')
+    def test_load_config_windows_paths(self):
+        # prepare (mix windows paths and posix paths for convenience)
+        mock_config = dict(repo_dir='foo\\repo', keys_dir='/tmp/bar/keys')
+        config_path = Repository.get_config_file_path()
+        config_path.write_text(json.dumps(mock_config))
+        print(config_path.read_text())
+        # test
+        config = Repository.load_config()
+        for key in mock_config.keys():
+            with self.subTest(msg=key):
+                self.assertEqual(mock_config[key].replace('\\', '/'), config[key])
+
     def test_from_config(self):
         temp_dir = self.temp_dir_path.resolve()
         repo_dir_abs = temp_dir / 'repo'