@@ -8,11 +8,10 @@
 
 import pytest
 
+from git.exc import GitCommandError
 from test.lib import TestBase
 from test.lib.helper import with_rw_directory
 
-import os.path
-
 
 class Tutorials(TestBase):
     def tearDown(self):
@@ -207,6 +206,14 @@ def update(self, op_code, cur_count, max_count=None, message=""):
         assert sm.module_exists()  # The submodule's working tree was checked out by update.
         # ![14-test_init_repo_object]
 
+    @pytest.mark.xfail(
+        os.name == "nt",
+        reason=(
+            "IndexFile.from_tree is broken on Windows (related to NamedTemporaryFile), see #1630.\n"
+            "'git read-tree --index-output=...' fails with 'fatal: unable to write new index file'."
+        ),
+        raises=GitCommandError,
+    )
     @with_rw_directory
     def test_references_and_objects(self, rw_dir):
         # [1-test_references_and_objects]
 
@@ -3,10 +3,13 @@
 
 from io import BytesIO
 from stat import S_IFDIR, S_IFREG, S_IFLNK, S_IXUSR
-from os import stat
+import os
 import os.path as osp
 
+import pytest
+
 from git import Git
+from git.exc import GitCommandError
 from git.index import IndexFile
 from git.index.fun import (
     aggressive_tree_merge,
@@ -34,6 +37,14 @@ def _assert_index_entries(self, entries, trees):
             assert (entry.path, entry.stage) in index.entries
         # END assert entry matches fully
 
+    @pytest.mark.xfail(
+        os.name == "nt",
+        reason=(
+            "IndexFile.from_tree is broken on Windows (related to NamedTemporaryFile), see #1630.\n"
+            "'git read-tree --index-output=...' fails with 'fatal: unable to write new index file'."
+        ),
+        raises=GitCommandError,
+    )
     def test_aggressive_tree_merge(self):
         # Head tree with additions, removals and modification compared to its predecessor.
         odb = self.rorepo.odb
@@ -291,12 +302,12 @@ def test_linked_worktree_traversal(self, rw_dir):
         rw_master.git.worktree("add", worktree_path, branch.name)
 
         dotgit = osp.join(worktree_path, ".git")
-        statbuf = stat(dotgit)
+        statbuf = os.stat(dotgit)
         self.assertTrue(statbuf.st_mode & S_IFREG)
 
         gitdir = find_worktree_git_dir(dotgit)
         self.assertIsNotNone(gitdir)
-        statbuf = stat(gitdir)
+        statbuf = os.stat(gitdir)
         self.assertTrue(statbuf.st_mode & S_IFDIR)
 
     def test_tree_entries_from_data_with_failing_name_decode_py3(self):
 
@@ -179,6 +179,14 @@ def add_bad_blob():
         except Exception as ex:
             assert "index.lock' could not be obtained" not in str(ex)
 
+    @pytest.mark.xfail(
+        os.name == "nt",
+        reason=(
+            "IndexFile.from_tree is broken on Windows (related to NamedTemporaryFile), see #1630.\n"
+            "'git read-tree --index-output=...' fails with 'fatal: unable to write new index file'."
+        ),
+        raises=GitCommandError,
+    )
     @with_rw_repo("0.1.6")
     def test_index_file_from_tree(self, rw_repo):
         common_ancestor_sha = "5117c9c8a4d3af19a9958677e45cda9269de1541"
@@ -229,6 +237,14 @@ def test_index_file_from_tree(self, rw_repo):
         # END for each blob
         self.assertEqual(num_blobs, len(three_way_index.entries))
 
+    @pytest.mark.xfail(
+        os.name == "nt",
+        reason=(
+            "IndexFile.from_tree is broken on Windows (related to NamedTemporaryFile), see #1630.\n"
+            "'git read-tree --index-output=...' fails with 'fatal: unable to write new index file'."
+        ),
+        raises=GitCommandError,
+    )
     @with_rw_repo("0.1.6")
     def test_index_merge_tree(self, rw_repo):
         # A bit out of place, but we need a different repo for this:
@@ -291,6 +307,14 @@ def test_index_merge_tree(self, rw_repo):
         self.assertEqual(len(unmerged_blobs), 1)
         self.assertEqual(list(unmerged_blobs.keys())[0], manifest_key[0])
 
+    @pytest.mark.xfail(
+        os.name == "nt",
+        reason=(
+            "IndexFile.from_tree is broken on Windows (related to NamedTemporaryFile), see #1630.\n"
+            "'git read-tree --index-output=...' fails with 'fatal: unable to write new index file'."
+        ),
+        raises=GitCommandError,
+    )
     @with_rw_repo("0.1.6")
     def test_index_file_diffing(self, rw_repo):
         # Default Index instance points to our index.
@@ -425,6 +449,14 @@ def _count_existing(self, repo, files):
 
     # END num existing helper
 
+    @pytest.mark.xfail(
+        os.name == "nt",
+        reason=(
+            "IndexFile.from_tree is broken on Windows (related to NamedTemporaryFile), see #1630.\n"
+            "'git read-tree --index-output=...' fails with 'fatal: unable to write new index file'."
+        ),
+        raises=GitCommandError,
+    )
     @with_rw_repo("0.1.6")
     def test_index_mutation(self, rw_repo):
         index = rw_repo.index
@@ -778,6 +810,14 @@ def make_paths():
         for absfile in absfiles:
             assert osp.isfile(absfile)
 
+    @pytest.mark.xfail(
+        os.name == "nt",
+        reason=(
+            "IndexFile.from_tree is broken on Windows (related to NamedTemporaryFile), see #1630.\n"
+            "'git read-tree --index-output=...' fails with 'fatal: unable to write new index file'."
+        ),
+        raises=GitCommandError,
+    )
     @with_rw_repo("HEAD")
     def test_compare_write_tree(self, rw_repo):
         """Test writing all trees, comparing them for equality."""
 
@@ -4,8 +4,11 @@
 # 3-Clause BSD License: https://opensource.org/license/bsd-3-clause/
 
 from itertools import chain
+import os
 from pathlib import Path
 
+import pytest
+
 from git import (
     Reference,
     Head,
@@ -215,6 +218,14 @@ def test_head_checkout_detached_head(self, rw_repo):
         assert isinstance(res, SymbolicReference)
         assert res.name == "HEAD"
 
+    @pytest.mark.xfail(
+        os.name == "nt",
+        reason=(
+            "IndexFile.from_tree is broken on Windows (related to NamedTemporaryFile), see #1630.\n"
+            "'git read-tree --index-output=...' fails with 'fatal: unable to write new index file'."
+        ),
+        raises=GitCommandError,
+    )
     @with_rw_repo("0.1.6")
     def test_head_reset(self, rw_repo):
         cur_head = rw_repo.head