diff --git a/studio/backend/utils/inference/inference_config.py b/studio/backend/utils/inference/inference_config.py
index a0377f9869..9efc281b0b 100644
--- a/studio/backend/utils/inference/inference_config.py
+++ b/studio/backend/utils/inference/inference_config.py
@@ -17,6 +17,7 @@ import structlog
 from loggers import get_logger
 
 from utils.models.model_config import load_model_defaults
+from utils.paths import is_local_path, normalize_path
 
 logger = get_logger(__name__)
 
@@ -93,8 +94,28 @@ def _has_specific_yaml(model_identifier: str) -> bool:
     if model_identifier.lower() in _REVERSE_MODEL_MAPPING:
         return True
 
-    # Check for exact filename match
-    model_filename = model_identifier.replace("/", "_") + ".yaml"
+    # For local filesystem paths (e.g. C:\Users\...\model on Windows),
+    # normalize backslashes so Path().parts splits correctly on POSIX/WSL,
+    # then try matching the last 1-2 path components against the registry
+    # (mirrors the logic in load_model_defaults).
+    _is_local = is_local_path(model_identifier)
+    _normalized = normalize_path(model_identifier) if _is_local else model_identifier
+
+    if _is_local:
+        parts = Path(_normalized).parts
+        for depth in (2, 1):
+            if len(parts) >= depth:
+                suffix = "/".join(parts[-depth:])
+                if suffix.lower() in _REVERSE_MODEL_MAPPING:
+                    return True
+        _lookup = Path(_normalized).name
+    else:
+        _lookup = model_identifier
+
+    # Check for exact filename match (basename for local paths to avoid
+    # passing absolute paths into rglob which raises
+    # "Non-relative patterns are unsupported" on Windows).
+    model_filename = _lookup.replace("/", "_") + ".yaml"
     for config_path in defaults_dir.rglob(model_filename):
         if config_path.is_file():
             return True
diff --git a/studio/backend/utils/models/model_config.py b/studio/backend/utils/models/model_config.py
index 5de3fd2cf9..f7d9b33542 100644
--- a/studio/backend/utils/models/model_config.py
+++ b/studio/backend/utils/models/model_config.py
@@ -1420,17 +1420,20 @@ def load_model_defaults(model_name: str) -> Dict[str, Any]:
                         return config
 
         # If model_name is a local path (e.g. /home/.../Spark-TTS-0.5B/LLM from
-        # adapter_config.json), try matching the last 1-2 path components against
-        # the registry (e.g. "Spark-TTS-0.5B/LLM").
-        if model_name not in _REVERSE_MODEL_MAPPING and (
-            model_name.startswith("/") or model_name.startswith(".")
-        ):
-            parts = Path(model_name).parts
+        # adapter_config.json, or C:\Users\...\model on Windows), try matching
+        # the last 1-2 path components against the registry
+        # (e.g. "Spark-TTS-0.5B/LLM").
+        _is_local_path = is_local_path(model_name)
+        # Normalize Windows backslash paths so Path().parts splits correctly
+        # on POSIX/WSL hosts (pathlib treats backslashes as literals on Linux).
+        _normalized = normalize_path(model_name) if _is_local_path else model_name
+        if model_name.lower() not in _REVERSE_MODEL_MAPPING and _is_local_path:
+            parts = Path(_normalized).parts
             for depth in [2, 1]:
                 if len(parts) >= depth:
                     suffix = "/".join(parts[-depth:])
-                    if suffix in _REVERSE_MODEL_MAPPING:
-                        canonical_file = _REVERSE_MODEL_MAPPING[suffix]
+                    if suffix.lower() in _REVERSE_MODEL_MAPPING:
+                        canonical_file = _REVERSE_MODEL_MAPPING[suffix.lower()]
                         for config_path in defaults_dir.rglob(canonical_file):
                             if config_path.is_file():
                                 with open(config_path, "r", encoding = "utf-8") as f:
@@ -1440,8 +1443,12 @@ def load_model_defaults(model_name: str) -> Dict[str, Any]:
                                     )
                                     return config
 
-        # Try exact model name match (for backward compatibility)
-        model_filename = model_name.replace("/", "_") + ".yaml"
+        # Try exact model name match (for backward compatibility).
+        # For local filesystem paths, use only the directory basename to
+        # avoid passing absolute paths (e.g. C:\...) into rglob which
+        # raises "Non-relative patterns are unsupported" on Windows.
+        _lookup_name = Path(_normalized).name if _is_local_path else model_name
+        model_filename = _lookup_name.replace("/", "_") + ".yaml"
         # Search in subfolders and root
         for config_path in defaults_dir.rglob(model_filename):
             if config_path.is_file():