From 58c8a3eadabcc139abd31360586f625adf908c8f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kai=20M=C3=BChlbauer?= <kmuehlbauer@wradlib.org>
Date: Sat, 16 Aug 2025 10:31:25 +0200
Subject: [PATCH 1/2] In case of misconfiguration of `unlimited_dims` warn
 instead of raise if originating from dataset.encoding

---
 xarray/backends/api.py        | 5 ++++-
 xarray/tests/test_backends.py | 4 ++--
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/xarray/backends/api.py b/xarray/backends/api.py
index 39698a686c0..4c4e5d30012 100644
--- a/xarray/backends/api.py
+++ b/xarray/backends/api.py
@@ -262,7 +262,10 @@ def _sanitize_unlimited_dims(dataset, unlimited_dims):
                 f"but not part of current dataset dimensions. "
                 f"Consider removing {undeclared_dims!r} from {msg_origin!r}."
             )
-            raise ValueError(msg)
+            if msg_origin == "unlimited_dims-kwarg":
+                raise ValueError(msg)
+            else:
+                emit_user_level_warning(msg)
         return unlimited_dims
 
 
diff --git a/xarray/tests/test_backends.py b/xarray/tests/test_backends.py
index c336fe7bd0d..87895b815d0 100644
--- a/xarray/tests/test_backends.py
+++ b/xarray/tests/test_backends.py
@@ -1399,8 +1399,8 @@ def test_encoding_unlimited_dims(self) -> None:
         # test unlimited_dims validation
         # https://github.com/pydata/xarray/issues/10549
         ds.encoding = {"unlimited_dims": "z"}
-        with pytest.raises(
-            ValueError,
+        with pytest.warns(
+            UserWarning,
             match=r"Unlimited dimension\(s\) .* declared in 'dataset.encoding'",
         ):
             with self.roundtrip(ds) as _:

From 697d64c4b8bb86ec32963f4c03deecf6a6f3bc21 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kai=20M=C3=BChlbauer?= <kmuehlbauer@wradlib.org>
Date: Sun, 17 Aug 2025 10:12:34 +0200
Subject: [PATCH 2/2] add whats-new.rst entry

---
 doc/whats-new.rst | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/doc/whats-new.rst b/doc/whats-new.rst
index 036119e2886..00abed27b9c 100644
--- a/doc/whats-new.rst
+++ b/doc/whats-new.rst
@@ -24,6 +24,8 @@ Deprecations
 
 Bug fixes
 ~~~~~~~~~
+- Warn instead of raise In case of misconfiguration of ``unlimited_dims`` originating from dataset.encoding, to prevent breaking users workflows (:issue:``, :pull:``).
+  By `Kai Mühlbauer <https://github.com/kmuehlbauer>`_.
 
 
 Documentation