diff --git a/extensions-builtin/sdnext-modernui b/extensions-builtin/sdnext-modernui
index 76eda2993..4b0966739 160000
--- a/extensions-builtin/sdnext-modernui
+++ b/extensions-builtin/sdnext-modernui
@@ -1 +1 @@
-Subproject commit 76eda29931a6308800466ec5ae582e19795d1e1a
+Subproject commit 4b0966739087b9712443d54be56b5dd70f01f6ca
diff --git a/modules/processing_helpers.py b/modules/processing_helpers.py
index 07936ad7c..284e9a63d 100644
--- a/modules/processing_helpers.py
+++ b/modules/processing_helpers.py
@@ -530,6 +530,8 @@ def update_sampler(p, sd_model, second_pass=False):
             else:
                 shared.opts.schedulers_use_karras = False
         sampler = sd_samplers.create_sampler(sampler.name, sd_model)
+        if sampler is None:
+            return
         sampler_options = []
         if sampler.config.get('use_karras_sigmas', False):
             sampler_options.append('karras')
diff --git a/modules/sd_samplers.py b/modules/sd_samplers.py
index ee89a652b..6ae5a5fe2 100644
--- a/modules/sd_samplers.py
+++ b/modules/sd_samplers.py
@@ -54,9 +54,8 @@ def create_sampler(name, model):
         shared.log.debug(f'Sampler default {type(model.scheduler).__name__}: {config}')
         return model.scheduler
     config = find_sampler_config(name)
-    if config is None:
-        shared.log.error(f'Attempting to use unknown sampler: {name}')
-        config = all_samplers[0]
+    if config is None or config.constructor is None:
+        return None
     if shared.backend == shared.Backend.ORIGINAL:
         sampler = config.constructor(model)
         sampler.config = config