diff --git a/lib/core/src/lib/form/components/widgets/file-viewer/file-viewer.widget.spec.ts b/lib/core/src/lib/form/components/widgets/file-viewer/file-viewer.widget.spec.ts
new file mode 100644
index 0000000000..01f77baa19
--- /dev/null
+++ b/lib/core/src/lib/form/components/widgets/file-viewer/file-viewer.widget.spec.ts
@@ -0,0 +1,83 @@
+/*!
+ * @license
+ * Copyright 2019 Alfresco Software, Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { FormModel } from '../core/form.model';
+import { TranslateModule } from '@ngx-translate/core';
+import { FormFieldModel } from '../core/form-field.model';
+import { FormService } from '../../../services/form.service';
+import { FileViewerWidgetComponent } from './file-viewer.widget';
+import { ComponentFixture, TestBed } from '@angular/core/testing';
+
+describe('FileViewerWidgetComponent', () => {
+    const fakeForm = new FormModel();
+    let widget: FileViewerWidgetComponent;
+    let formServiceStub: Partial<FormService>;
+    let fixture: ComponentFixture<FileViewerWidgetComponent>;
+
+    const fakePngAnswer: any = {
+        id: '1933',
+        link: false,
+        isExternal: false,
+        relatedContent: false,
+        contentAvailable: true,
+        name: 'a_png_file.png',
+        simpleType: 'image',
+        mimeType: 'image/png',
+        previewStatus: 'queued',
+        thumbnailStatus: 'queued',
+        created: '2022-10-14T17:17:37.099Z',
+        createdBy: { id: 1001, firstName: 'Admin', lastName: 'admin', email: 'admin@example.com' }
+    };
+
+    beforeEach(() => {
+        TestBed.configureTestingModule({
+            imports: [
+                TranslateModule.forRoot()
+            ],
+            declarations: [ FileViewerWidgetComponent ],
+            providers: [ { provide: FormService, useValue: formServiceStub } ]
+          });
+
+        formServiceStub = TestBed.inject(FormService);
+        fixture = TestBed.createComponent(FileViewerWidgetComponent);
+        widget = fixture.componentInstance;
+    });
+
+    it('should set the file id corretly when the field value is an array', (done) => {
+        const fakeField = new FormFieldModel(fakeForm, { id: 'fakeField', value: [fakePngAnswer] });
+        widget.field = fakeField;
+
+        fixture.detectChanges();
+
+        fixture.whenStable().then(() => {
+            expect(widget.field.value).toBe('1933');
+            done();
+        });
+    });
+
+    it('should set the file id corretly when the field value is a string', (done) => {
+        const fakeField = new FormFieldModel(fakeForm, { id: 'fakeField', value: 'fakeValue' });
+        widget.field = fakeField;
+
+        fixture.detectChanges();
+
+        fixture.whenStable().then(() => {
+            expect(widget.field.value).toBe('fakeValue');
+            done();
+        });
+    });
+});
diff --git a/lib/core/src/lib/form/components/widgets/file-viewer/file-viewer.widget.ts b/lib/core/src/lib/form/components/widgets/file-viewer/file-viewer.widget.ts
index 03a5cf6b79..b0b1b672aa 100644
--- a/lib/core/src/lib/form/components/widgets/file-viewer/file-viewer.widget.ts
+++ b/lib/core/src/lib/form/components/widgets/file-viewer/file-viewer.widget.ts
@@ -15,7 +15,7 @@
  * limitations under the License.
  */
 
-import { Component, ViewEncapsulation } from '@angular/core';
+import { Component, OnInit, ViewEncapsulation } from '@angular/core';
 import { FormService } from '../../../services/form.service';
 import { WidgetComponent } from '../widget.component';
 
@@ -38,9 +38,18 @@ import { WidgetComponent } from '../widget.component';
     },
     encapsulation: ViewEncapsulation.None
 })
-export class FileViewerWidgetComponent extends WidgetComponent {
-
+export class FileViewerWidgetComponent extends WidgetComponent implements OnInit {
     constructor(formService: FormService) {
         super(formService);
     }
+
+    ngOnInit(): void {
+        if (this.field &&
+            this.field.value &&
+            Array.isArray(this.field.value) &&
+            this.field.value.length) {
+            const file = this.field.value[0];
+            this.field.value = file.id;
+        }
+    }
 }