diff --git a/backend/open_webui/utils/middleware.py b/backend/open_webui/utils/middleware.py
index d377446249..94521d6ce0 100644
--- a/backend/open_webui/utils/middleware.py
+++ b/backend/open_webui/utils/middleware.py
@@ -97,6 +97,7 @@ from open_webui.utils.misc import (
     convert_logit_bias_input_to_json,
     get_content_from_message,
     convert_output_to_messages,
+    strip_empty_content_blocks,
 )
 from open_webui.utils.tools import (
     get_tools,
@@ -2634,6 +2635,10 @@ async def process_chat_payload(request, form_data, user, metadata, model):
             }
         )
 
+    # Strip empty text content blocks from multimodal messages
+    # to prevent errors from providers like Gemini and Claude
+    form_data['messages'] = strip_empty_content_blocks(form_data.get('messages', []))
+
     return form_data, metadata, events
 
 
diff --git a/backend/open_webui/utils/misc.py b/backend/open_webui/utils/misc.py
index dec97abd25..91217b3c23 100644
--- a/backend/open_webui/utils/misc.py
+++ b/backend/open_webui/utils/misc.py
@@ -401,6 +401,31 @@ def append_or_update_assistant_message(content: str, messages: list[dict]):
     return messages
 
 
+def strip_empty_content_blocks(messages: list[dict]) -> list[dict]:
+    """
+    Remove empty text content blocks from multimodal message content arrays.
+
+    Providers like Gemini and Claude reject messages where a text block has
+    an empty string.  This can happen when a user sends only file/image
+    attachments without typing any text.
+    """
+    for message in messages:
+        content = message.get('content')
+        if isinstance(content, list):
+            cleaned = [
+                block
+                for block in content
+                if not (
+                    isinstance(block, dict)
+                    and block.get('type') == 'text'
+                    and not block.get('text', '').strip()
+                )
+            ]
+            if cleaned:
+                message['content'] = cleaned
+    return messages
+
+
 def openai_chat_message_template(model: str):
     return {
         'id': f'{model}-{str(uuid.uuid4())}',
diff --git a/src/lib/components/chat/MessageInput/InputVariablesModal.svelte b/src/lib/components/chat/MessageInput/InputVariablesModal.svelte
index b50ed38395..5a6cfd4346 100644
--- a/src/lib/components/chat/MessageInput/InputVariablesModal.svelte
+++ b/src/lib/components/chat/MessageInput/InputVariablesModal.svelte
@@ -17,7 +17,7 @@
 
 	export let onSave = (e) => {};
 
-	let loading = false;
+	let loading = true;
 	let variableValues = {};
 
 	const submitHandler = async () => {