diff --git a/eslint-suppressions.json b/eslint-suppressions.json
index 227edc2fd71..2612b2c0400 100644
--- a/eslint-suppressions.json
+++ b/eslint-suppressions.json
@@ -3383,11 +3383,6 @@
       "count": 1
     }
   },
-  "public/app/features/transformers/editors/GroupByTransformerEditor.tsx": {
-    "@typescript-eslint/consistent-type-assertions": {
-      "count": 1
-    }
-  },
   "public/app/features/transformers/editors/GroupToNestedTableTransformerEditor.tsx": {
     "no-restricted-syntax": {
       "count": 1
diff --git a/public/app/features/transformers/editors/GroupByTransformerEditor.tsx b/public/app/features/transformers/editors/GroupByTransformerEditor.tsx
index ebd2a55661d..b84753a1b20 100644
--- a/public/app/features/transformers/editors/GroupByTransformerEditor.tsx
+++ b/public/app/features/transformers/editors/GroupByTransformerEditor.tsx
@@ -4,7 +4,6 @@ import { useCallback } from 'react';
 import {
   DataTransformerID,
   ReducerID,
-  SelectableValue,
   standardTransformers,
   TransformerRegistryItem,
   TransformerUIProps,
@@ -13,12 +12,12 @@ import {
 } from '@grafana/data';
 import { GroupByFieldOptions, GroupByOperationID, GroupByTransformerOptions } from '@grafana/data/internal';
 import { t } from '@grafana/i18n';
-import { useTheme2, Select, StatsPicker, InlineField, Stack, Alert } from '@grafana/ui';
+import { useTheme2, StatsPicker, InlineField, Stack, Alert, Combobox, ComboboxOption } from '@grafana/ui';
 
 import { getTransformationContent } from '../docs/getTransformationContent';
 import darkImage from '../images/dark/groupBy.svg';
 import lightImage from '../images/light/groupBy.svg';
-import { useAllFieldNamesFromDataFrames } from '../utils';
+import { DataFieldsErrorWrapper } from '../utils';
 
 interface FieldProps {
   fieldName: string;
@@ -26,9 +25,11 @@ interface FieldProps {
   onConfigChange: (config: GroupByFieldOptions) => void;
 }
 
-const GroupByTransformerEditor = ({ input, options, onChange }: TransformerUIProps<GroupByTransformerOptions>) => {
-  const fieldNames = useAllFieldNamesFromDataFrames(input, true);
+interface GroupByTransformerEditorProps extends TransformerUIProps<GroupByTransformerOptions> {
+  fieldNames: string[];
+}
 
+export const GroupByTransformerEditorBase = ({ options, onChange, fieldNames }: GroupByTransformerEditorProps) => {
   const onConfigChange = useCallback(
     (fieldName: string) => (config: GroupByFieldOptions) => {
       onChange({
@@ -84,16 +85,20 @@ const GroupByTransformerEditor = ({ input, options, onChange }: TransformerUIPro
   );
 };
 
+const GroupByTransformerEditor = DataFieldsErrorWrapper(GroupByTransformerEditorBase, {
+  withBaseFieldNames: true,
+});
+
 const GroupByFieldConfiguration = ({ fieldName, config, onConfigChange }: FieldProps) => {
   const theme = useTheme2();
 
   const styles = getStyles(theme);
 
   const onChange = useCallback(
-    (value: SelectableValue<GroupByOperationID | null>) => {
+    (option: ComboboxOption<GroupByOperationID> | null) => {
       onConfigChange({
         aggregations: config?.aggregations ?? [],
-        operation: value?.value ?? null,
+        operation: option?.value ?? null,
       });
     },
     [config, onConfigChange]
@@ -114,7 +119,7 @@ const GroupByFieldConfiguration = ({ fieldName, config, onConfigChange }: FieldP
     <InlineField className={styles.label} label={fieldName} grow shrink>
       <Stack gap={0.5} direction="row">
         <div className={styles.operation}>
-          <Select
+          <Combobox
             options={options}
             value={config?.operation}
             placeholder={t('transformers.group-by-field-configuration.placeholder-ignored', 'Ignored')}
@@ -129,8 +134,8 @@ const GroupByFieldConfiguration = ({ fieldName, config, onConfigChange }: FieldP
             placeholder={t('transformers.group-by-field-configuration.placeholder-select-stats', 'Select stats')}
             allowMultiple
             stats={config.aggregations}
-            onChange={(stats) => {
-              onConfigChange({ ...config, aggregations: stats as ReducerID[] });
+            onChange={(stats: string[]) => {
+              onConfigChange({ ...config, aggregations: stats.filter((stat): stat is ReducerID => stat in ReducerID) });
             }}
             filterOptions={(option) =>
               config?.operation === GroupByOperationID.groupBy ? option.id === ReducerID.count : true
diff --git a/public/app/features/transformers/utils.test.ts b/public/app/features/transformers/utils.test.ts
index 0225476e0a7..b5f6959e108 100644
--- a/public/app/features/transformers/utils.test.ts
+++ b/public/app/features/transformers/utils.test.ts
@@ -1,6 +1,16 @@
+import { act, render, screen } from '@testing-library/react';
+import { createElement } from 'react';
+
 import { FieldType, toDataFrame } from '@grafana/data';
 
-import { getAllFieldNamesFromDataFrames, numberOrVariableValidator } from './utils';
+import { GroupByTransformerEditorBase } from './editors/GroupByTransformerEditor';
+import {
+  DataFieldsErrorWrapper,
+  detectPartialQueryFailures,
+  getAllFieldNamesFromDataFrames,
+  numberOrVariableValidator,
+  TIMEOUT,
+} from './utils';
 
 describe('validator', () => {
   it('validates a positive number', () => {
@@ -112,3 +122,87 @@ describe('useAllFieldNamesFromDataFrames', () => {
     expect(names).toEqual(['T', 't', 'n', 's', 't2']);
   });
 });
+
+describe('detectPartialQueryFailures', () => {
+  it('returns false when all queries are successful', () => {
+    const frames = [toDataFrame({ fields: [{ name: 'test', type: FieldType.string, values: ['a'] }] })];
+    expect(detectPartialQueryFailures(frames)).toBe(false);
+  });
+
+  it('returns true when some queries are successful and some are not', () => {
+    const frames = [
+      toDataFrame({ fields: [] }),
+      toDataFrame({ fields: [{ name: 'test', type: FieldType.string, values: ['a'] }] }),
+    ];
+    expect(detectPartialQueryFailures(frames)).toBe(true);
+  });
+});
+
+describe('DataFieldsErrorWrapper', () => {
+  const WrappedDashboard = DataFieldsErrorWrapper(GroupByTransformerEditorBase, { withBaseFieldNames: true });
+
+  beforeEach(() => {
+    jest.useFakeTimers();
+  });
+
+  afterEach(() => {
+    act(() => jest.runOnlyPendingTimers());
+    jest.useRealTimers();
+  });
+
+  test('shows no error message if there are fields', () => {
+    const mockProps = {
+      input: [toDataFrame({ fields: [{ name: 'test', type: FieldType.string, values: ['a'] }] })],
+      options: { fields: {} },
+      onChange: jest.fn(),
+    };
+    act(() => render(createElement(WrappedDashboard, mockProps)));
+    expect(screen.queryByText(/One or more queries failed/)).not.toBeInTheDocument();
+  });
+
+  test('shows error message after debounce delay when there are no fields (e.g., datasource error or failed query', () => {
+    const mockProps = {
+      input: [toDataFrame({ fields: [] })],
+      options: { fields: {} },
+      onChange: jest.fn(),
+    };
+
+    act(() => render(createElement(WrappedDashboard, mockProps)));
+
+    // It should not show the error message immediately
+    expect(screen.queryByText(/One or more queries failed/)).not.toBeInTheDocument();
+
+    // It should show the error message after the debounce delay
+    act(() => jest.advanceTimersByTime(TIMEOUT));
+    expect(screen.getByText(/One or more queries failed/)).toBeInTheDocument();
+  });
+
+  test('shows error message for mixed query results (some successful, some failed)', () => {
+    const mockProps = {
+      input: [
+        toDataFrame({
+          refId: 'A',
+          fields: [
+            { name: 'time', type: FieldType.time, values: [1, 2, 3] },
+            { name: 'temperature', type: FieldType.number, values: [20, 21, 22] },
+          ],
+        }),
+        toDataFrame({ refId: 'B', fields: [] }),
+      ],
+      options: { fields: {} },
+      onChange: jest.fn(),
+    };
+
+    act(() => render(createElement(WrappedDashboard, mockProps)));
+
+    // It should not show the error message immediately
+    expect(screen.queryByText(/One or more queries failed/)).not.toBeInTheDocument();
+
+    // It should show the error message after the debounce delay
+    act(() => jest.advanceTimersByTime(TIMEOUT));
+    expect(screen.getByText(/One or more queries failed/)).toBeInTheDocument();
+
+    // Should show available field names
+    expect(screen.getByText('time')).toBeInTheDocument();
+  });
+});
diff --git a/public/app/features/transformers/utils.ts b/public/app/features/transformers/utils.ts
index 55358295b07..031f232916c 100644
--- a/public/app/features/transformers/utils.ts
+++ b/public/app/features/transformers/utils.ts
@@ -1,4 +1,6 @@
-import { useMemo } from 'react';
+import { useMemo, useState } from 'react';
+import * as React from 'react';
+import { useDebounce } from 'react-use';
 
 import {
   DataFrame,
@@ -9,9 +11,11 @@ import {
   VariableOrigin,
   VariableSuggestion,
   SpecialValue,
+  TransformerUIProps,
 } from '@grafana/data';
 import { t } from '@grafana/i18n';
 import { getTemplateSrv } from '@grafana/runtime';
+import { FieldValidationMessage } from '@grafana/ui';
 
 import { variableRegex } from '../variables/utils';
 
@@ -45,10 +49,62 @@ export const getAllFieldNamesFromDataFrames = (frames: DataFrame[], withBaseFiel
   return names;
 };
 
+export const detectPartialQueryFailures = (frames: DataFrame[]) => {
+  const hasSuccessful = frames.some(({ fields }) => fields.length > 0);
+  const hasEmpty = frames.some(({ fields }) => !fields.length);
+  return hasSuccessful && hasEmpty;
+};
+
 export function useAllFieldNamesFromDataFrames(frames: DataFrame[], withBaseFieldNames = false): string[] {
   return useMemo(() => getAllFieldNamesFromDataFrames(frames, withBaseFieldNames), [frames, withBaseFieldNames]);
 }
 
+export const TransformerMissingFieldsMessage = () => {
+  return React.createElement(
+    FieldValidationMessage,
+    null,
+    t(
+      'transformers.query-validation-message',
+      'One or more queries failed to return fields. This transformation can only reference fields from queries with a successful and visible result.'
+    )
+  );
+};
+
+type ExpandedTransformerUIProps<T> = TransformerUIProps<T> & { fieldNames: string[] };
+type DataFieldsErrorWrapperOptions = { withBaseFieldNames?: boolean };
+
+export const TIMEOUT = 300;
+
+export function DataFieldsErrorWrapper<T>(
+  Component: React.ComponentType<ExpandedTransformerUIProps<T>>,
+  { withBaseFieldNames = false }: DataFieldsErrorWrapperOptions = {}
+): React.ComponentType<TransformerUIProps<T>> {
+  function WrappedComponent({ input, ...props }: TransformerUIProps<T>) {
+    const [showError, setShowError] = useState(false);
+
+    const fieldNames = useAllFieldNamesFromDataFrames(input, withBaseFieldNames);
+    const hasPartialQueryFailures = detectPartialQueryFailures(input);
+    const hasErrorCondition = fieldNames.length === 0 || hasPartialQueryFailures;
+
+    useDebounce(() => setShowError(hasErrorCondition), TIMEOUT, [hasErrorCondition]);
+
+    const wrappedComponent = React.createElement(Component, { ...props, input, fieldNames });
+
+    if (showError) {
+      return React.createElement(
+        React.Fragment,
+        null,
+        React.createElement(TransformerMissingFieldsMessage),
+        wrappedComponent
+      );
+    }
+
+    return wrappedComponent;
+  }
+
+  return WrappedComponent;
+}
+
 export function getDistinctLabels(input: DataFrame[]): Set<string> {
   const distinct = new Set<string>();
   for (const frame of input) {
diff --git a/public/locales/en-US/grafana.json b/public/locales/en-US/grafana.json
index ed0738c373a..2c9439a2df2 100644
--- a/public/locales/en-US/grafana.json
+++ b/public/locales/en-US/grafana.json
@@ -13685,6 +13685,7 @@
         }
       }
     },
+    "query-validation-message": "One or more queries failed to return fields. This transformation can only reference fields from queries with a successful and visible result.",
     "range-matcher-editor": {
       "and": "and",
       "placeholder-from": "From",