diff --git a/packages/decap-cms-backend-gitlab/src/__tests__/gitlab.spec.js b/packages/decap-cms-backend-gitlab/src/__tests__/gitlab.spec.js
index 4953ac3e4a0d..8df225359b10 100644
--- a/packages/decap-cms-backend-gitlab/src/__tests__/gitlab.spec.js
+++ b/packages/decap-cms-backend-gitlab/src/__tests__/gitlab.spec.js
@@ -432,6 +432,7 @@ describe('gitlab backend', () => {
       expect(entries).toEqual({
         cursor: expect.any(Cursor),
         pagination: 1,
+        errors: [],
         entries: expect.arrayContaining(
           tree.map(file => expect.objectContaining({ path: file.path })),
         ),
@@ -445,7 +446,7 @@ describe('gitlab backend', () => {
       tree.forEach(file => interceptFiles(backend, file.path));
 
       interceptCollection(backend, collectionManyEntriesConfig, { repeat: 5 });
-      const entries = await backend.listAllEntries(fromJS(collectionManyEntriesConfig));
+      const { entries } = await backend.listAllEntries(fromJS(collectionManyEntriesConfig));
 
       expect(entries).toEqual(
         expect.arrayContaining(tree.map(file => expect.objectContaining({ path: file.path }))),
@@ -463,6 +464,7 @@ describe('gitlab backend', () => {
         entries: expect.arrayContaining(
           files.map(file => expect.objectContaining({ path: file.file })),
         ),
+        errors: [],
       });
       expect(entries.entries).toHaveLength(2);
     });
diff --git a/packages/decap-cms-core/src/__tests__/backend.spec.js b/packages/decap-cms-core/src/__tests__/backend.spec.js
index c673c19a01c4..5826c0ddb332 100644
--- a/packages/decap-cms-core/src/__tests__/backend.spec.js
+++ b/packages/decap-cms-core/src/__tests__/backend.spec.js
@@ -655,15 +655,15 @@ describe('Backend', () => {
       backend = new Backend(implementation, { config: {}, backendName: 'github' });
       backend.listAllEntries = jest.fn(collection => {
         if (collection.get('name') === 'posts') {
-          return Promise.resolve(posts);
+          return Promise.resolve({ entries: posts });
         }
         if (collection.get('name') === 'pages') {
-          return Promise.resolve(pages);
+          return Promise.resolve({ entries: pages });
         }
         if (collection.get('name') === 'files') {
-          return Promise.resolve(files);
+          return Promise.resolve({ entries: files });
         }
-        return Promise.resolve([]);
+        return Promise.resolve({ entries: [] });
       });
     });
 
diff --git a/packages/decap-cms-core/src/actions/entries.ts b/packages/decap-cms-core/src/actions/entries.ts
index f9f52236d93c..f08c5d933df0 100644
--- a/packages/decap-cms-core/src/actions/entries.ts
+++ b/packages/decap-cms-core/src/actions/entries.ts
@@ -164,7 +164,7 @@ export async function getAllEntries(state: State, collection: Collection) {
   const provider: Backend = integration
     ? getIntegrationProvider(state.integrations, backend.getToken, integration)
     : backend;
-  const entries = await provider.listAllEntries(collection);
+  const { entries } = await provider.listAllEntries(collection);
   return entries;
 }
 
@@ -609,9 +609,10 @@ export function loadEntries(collection: Collection, page = 0) {
         cursor: Cursor;
         pagination: number;
         entries: EntryValue[];
+        errors?: string[];
       } = await (loadAllEntries
         ? // nested collections require all entries to construct the tree
-          provider.listAllEntries(collection).then((entries: EntryValue[]) => ({ entries }))
+          provider.listAllEntries(collection)
         : provider.listEntries(collection, page));
       response = {
         ...response,
@@ -630,6 +631,19 @@ export function loadEntries(collection: Collection, page = 0) {
           : Cursor.create(response.cursor),
       };
 
+      response.errors?.forEach(error => {
+        dispatch(
+          addNotification({
+            message: {
+              details: error,
+              key: 'ui.toast.duplicateFrontmatterKey',
+            },
+            type: 'warning',
+            dismissAfter: 8000,
+          }),
+        );
+      });
+
       dispatch(
         entriesLoaded(
           collection,
diff --git a/packages/decap-cms-core/src/backend.ts b/packages/decap-cms-core/src/backend.ts
index 0025b26f4308..b0d0c2b25093 100644
--- a/packages/decap-cms-core/src/backend.ts
+++ b/packages/decap-cms-core/src/backend.ts
@@ -521,7 +521,12 @@ export class Backend {
         },
       ),
     );
+
     const formattedEntries = entries.map(this.entryWithFormat(collection));
+    const errors = formattedEntries
+      .filter(e => e.parseError)
+      .map(e => `${e.parseError}. In ${e.path}`);
+
     // If this collection has a "filter" property, filter entries accordingly
     const collectionFilter = collection.get('filter');
     const filteredEntries = collectionFilter
@@ -531,10 +536,9 @@ export class Backend {
     if (hasI18n(collection)) {
       const extension = selectFolderEntryExtension(collection);
       const groupedEntries = groupEntries(collection, extension, filteredEntries);
-      return groupedEntries;
+      return { entries: groupedEntries, errors };
     }
-
-    return filteredEntries;
+    return { entries: filteredEntries, errors };
   }
 
   async listEntries(collection: Collection) {
@@ -574,10 +578,14 @@ export class Backend {
       cursorType: 'collectionEntries',
       collection,
     });
+
+    const { entries, errors } = this.processEntries(loadedEntries, collection);
+
     return {
-      entries: this.processEntries(loadedEntries, collection),
+      entries,
       pagination: cursor.meta?.get('page'),
       cursor,
+      errors,
     };
   }
 
@@ -601,14 +609,17 @@ export class Backend {
     }
 
     const response = await this.listEntries(collection);
-    const { entries } = response;
+    const { entries, errors } = response;
     let { cursor } = response;
     while (cursor && cursor.actions!.includes('next')) {
       const { entries: newEntries, cursor: newCursor } = await this.traverseCursor(cursor, 'next');
       entries.push(...newEntries);
       cursor = newCursor;
     }
-    return entries;
+    return {
+      entries,
+      errors,
+    };
   }
 
   async search(collections: Collection[], searchTerm: string) {
@@ -646,7 +657,7 @@ export class Backend {
           ];
         }
         const filteredSearchFields = searchFields.filter(Boolean) as string[];
-        const collectionEntries = await this.listAllEntries(collection);
+        const collectionEntries = (await this.listAllEntries(collection)).entries;
         return fuzzy.filter(searchTerm, collectionEntries, {
           extract: extractSearchFields(uniq(filteredSearchFields)),
         });
@@ -680,7 +691,7 @@ export class Backend {
     file?: string,
     limit?: number,
   ) {
-    let entries = await this.listAllEntries(collection);
+    let { entries } = await this.listAllEntries(collection);
     if (file) {
       entries = entries.filter(e => e.slug === file);
     }
@@ -710,7 +721,7 @@ export class Backend {
     const collection = data.get('collection') as Collection;
     return this.implementation!.traverseCursor!(unwrappedCursor, action).then(
       async ({ entries, cursor: newCursor }) => ({
-        entries: this.processEntries(entries, collection),
+        entries: this.processEntries(entries, collection).entries,
         cursor: Cursor.create(newCursor).wrapData({
           cursorType: 'collectionEntries',
           collection,
@@ -877,7 +888,11 @@ export class Backend {
       const format = resolveFormat(collection, entry);
       if (entry && entry.raw !== undefined) {
         const data = (format && attempt(format.fromFile.bind(format, entry.raw))) || {};
-        if (isError(data)) console.error(data);
+        if (isError(data)) {
+          console.warn(data.message, '\n', data.stack);
+          entry = Object.assign(entry, { parseError: data.message });
+        }
+
         return Object.assign(entry, { data: isError(data) ? {} : data });
       }
       return format.fromFile(entry);
diff --git a/packages/decap-cms-core/src/valueObjects/Entry.ts b/packages/decap-cms-core/src/valueObjects/Entry.ts
index 23497db92ae5..aca0bdd62042 100644
--- a/packages/decap-cms-core/src/valueObjects/Entry.ts
+++ b/packages/decap-cms-core/src/valueObjects/Entry.ts
@@ -35,6 +35,7 @@ export interface EntryValue {
   updatedOn: string;
   status?: string;
   meta: { path?: string };
+  parseError?: string;
   i18n?: {
     // eslint-disable-next-line @typescript-eslint/no-explicit-any
     [locale: string]: any;
diff --git a/packages/decap-cms-locales/src/en/index.js b/packages/decap-cms-locales/src/en/index.js
index 2e6c7b26b01f..f8af29a6fc83 100644
--- a/packages/decap-cms-locales/src/en/index.js
+++ b/packages/decap-cms-locales/src/en/index.js
@@ -286,6 +286,7 @@ const en = {
       onFailToDelete: 'Failed to delete entry: %{details}',
       onFailToUpdateStatus: 'Failed to update status: %{details}',
       missingRequiredField: "Oops, you've missed a required field. Please complete before saving.",
+      duplicateFrontmatterKey: 'Duplicate key in frontmatter. %{details}',
       entrySaved: 'Entry saved',
       entryPublished: 'Entry published',
       entryUnpublished: 'Entry unpublished',