diff --git a/lib/process-services/src/lib/mock/task/task-details.mock.ts b/lib/process-services/src/lib/mock/task/task-details.mock.ts
index bf04da9c1f..55e42d040d 100644
--- a/lib/process-services/src/lib/mock/task/task-details.mock.ts
+++ b/lib/process-services/src/lib/mock/task/task-details.mock.ts
@@ -206,6 +206,41 @@ export let initiatorCanCompleteTaskDetailsMock = new TaskDetailsModel({
     taskDefinitionKey: 'sid-DDECD9E4-0299-433F-9193-C3D905C3EEBE',
     executionId: '86',
     involvedGroups: [],
+    involvedPeople: [],
+    memberOfCandidateUsers: false,
+    managerOfCandidateGroup: false,
+    memberOfCandidateGroup: false
+});
+
+export let initiatorWithCandidatesTaskDetailsMock = new TaskDetailsModel({
+    id: '91',
+    name: 'Request translation',
+    description: null,
+    category: null,
+    assignee: null,
+    created: '2016-11-03T15:25:42.749+0000',
+    dueDate: null,
+    endDate: null,
+    duration: null,
+    priority: 50,
+    parentTaskId: null,
+    parentTaskName: null,
+    processInstanceId: '86',
+    processInstanceName: null,
+    processDefinitionId: 'TranslationProcess:2:8',
+    processDefinitionName: 'Translation Process',
+    processDefinitionDescription: null,
+    processDefinitionKey: 'TranslationProcess',
+    processDefinitionCategory: 'http://www.activiti.org/processdef',
+    processDefinitionVersion: 2,
+    processDefinitionDeploymentId: '5',
+    formKey: '4',
+    processInstanceStartUserId: '1001',
+    initiatorCanCompleteTask: true,
+    adhocTaskCanBeReassigned: false,
+    taskDefinitionKey: 'sid-DDECD9E4-0299-433F-9193-C3D905C3EEBE',
+    executionId: '86',
+    involvedGroups: [],
     involvedPeople: [
         {
             id: 1001,
@@ -220,9 +255,9 @@ export let initiatorCanCompleteTaskDetailsMock = new TaskDetailsModel({
             email: 'fake@app.activiti.com'
         }
     ],
-    memberOfCandidateUsers: false,
-    managerOfCandidateGroup: false,
-    memberOfCandidateGroup: false
+    memberOfCandidateUsers: true,
+    managerOfCandidateGroup: true,
+    memberOfCandidateGroup: true
 });
 
 export let taskDetailsWithOutAssigneeMock = new TaskDetailsModel({
@@ -316,10 +351,13 @@ export let claimedTaskDetailsMock = new TaskDetailsModel({
     endDate: null,
     duration: null,
     priority: 50,
+    formKey: '4',
     parentTaskId: null,
     parentTaskName: null,
     processInstanceId: '86',
     processInstanceName: null,
+    processInstanceStartUserId: '1002',
+    initiatorCanCompleteTask: false,
     processDefinitionId: 'TranslationProcess:2:8',
     processDefinitionName: 'Translation Process',
     involvedGroups: [
@@ -507,7 +545,7 @@ export let taskDetailsWithOutFormMock = new TaskDetailsModel({
     'name': 'Request translation',
     'description': 'fake description',
     'category': null,
-    'assignee': {'id': 1001, 'firstName': 'Admin', 'lastName': 'Paul', 'email': 'my@mymail.com' },
+    'assignee': {'id': 1001, 'firstName': 'Admin', 'lastName': 'Paul', 'email': 'fake-email@gmail.com' },
     'created': '2016-11-03T15:25:42.749+0000',
     'dueDate': '2016-11-03T15:25:42.749+0000',
     'endDate': null,
diff --git a/lib/process-services/src/lib/task-list/components/task-form/task-form.component.html b/lib/process-services/src/lib/task-list/components/task-form/task-form.component.html
index 3ba824ba04..85d96084d9 100644
--- a/lib/process-services/src/lib/task-list/components/task-form/task-form.component.html
+++ b/lib/process-services/src/lib/task-list/components/task-form/task-form.component.html
@@ -5,7 +5,6 @@
     [showValidationIcon]="showFormValidationIcon"
     [showRefreshButton]="showFormRefreshButton"
     [showCompleteButton]="showFormCompleteButton"
-    [disableCompleteButton]="!isCompleteButtonEnabled()"
     [showSaveButton]="isSaveButtonVisible()"
     [readOnly]="isReadOnlyForm()"
     [fieldValidators]="fieldValidators"
@@ -61,10 +60,11 @@
             </mat-card-content>
             <mat-card-actions class="adf-task-form-actions">
                 <ng-template [ngTemplateOutlet]="taskFormButtons"></ng-template>
-                <button id="adf-no-form-cancel-button" mat-button *ngIf="showCancelButton" (click)="onCancel()">
-                    {{'ADF_TASK_FORM.EMPTY_FORM.BUTTONS.CANCEL' | translate}}
-                </button>
-                <button mat-button *ngIf="!isCompletedTask()" color="primary" (click)="onCompleteTask()" id="adf-no-form-complete-button">
+                <button mat-button
+                    *ngIf="!isCompletedTask()" id="adf-no-form-complete-button"
+                    color="primary"
+                    [disabled]="canCompleteNoFormTask()"
+                    (click)="onCompleteTask()">
                     {{'ADF_TASK_FORM.EMPTY_FORM.BUTTONS.COMPLETE' | translate}}
                 </button>
             </mat-card-actions>
@@ -73,18 +73,25 @@
   </ng-template>
 
   <ng-template #taskFormButtons>
+        <button mat-button id="adf-no-form-cancel-button" 
+            *ngIf="showCancelButton"
+            (click)="onCancel()">
+            {{'ADF_TASK_FORM.EMPTY_FORM.BUTTONS.CANCEL' | translate}}
+        </button>
         <button mat-button data-automation-id="adf-task-form-claim-button"
             *ngIf="isTaskClaimable()" 
             adf-claim-task
             [taskId]="taskId"
-            (success)="onClaimTask($event)">
+            (success)="onClaimTask($event)"
+            (error)="onClaimTaskError($event)">
             {{ 'ADF_TASK_LIST.DETAILS.BUTTON.CLAIM' | translate }}
         </button>
         <button mat-button data-automation-id="adf-task-form-unclaim-button"
             *ngIf="isTaskClaimedByCandidateMember()"
             adf-unclaim-task
             [taskId]="taskId"
-            (success)="onUnclaimTask($event)">
+            (success)="onUnclaimTask($event)"
+            (error)="onUnclaimTaskError($event)">
             {{ 'ADF_TASK_LIST.DETAILS.BUTTON.UNCLAIM' | translate }}
         </button>
   </ng-template>
diff --git a/lib/process-services/src/lib/task-list/components/task-form/task-form.component.spec.ts b/lib/process-services/src/lib/task-list/components/task-form/task-form.component.spec.ts
index a14c149544..bfae1e5c4b 100644
--- a/lib/process-services/src/lib/task-list/components/task-form/task-form.component.spec.ts
+++ b/lib/process-services/src/lib/task-list/components/task-form/task-form.component.spec.ts
@@ -40,7 +40,8 @@ import {
     initiatorCanCompleteTaskDetailsMock,
     taskDetailsWithOutCandidateGroup,
     claimedTaskDetailsMock,
-    claimedByGroupMemberMock
+    claimedByGroupMemberMock,
+    initiatorWithCandidatesTaskDetailsMock
 } from '../../../mock/task/task-details.mock';
 import { TaskDetailsModel } from '../../models/task-details.model';
 import { ProcessTestingModule } from '../../../testing/process.testing.module';
@@ -80,7 +81,7 @@ describe('TaskFormComponent', () => {
         taskDetailsMock.processDefinitionId = null;
         spyOn(formService, 'getTask').and.returnValue(of(taskDetailsMock));
         authService = TestBed.get(AuthenticationService);
-        getBpmLoggedUserSpy = spyOn(authService, 'getBpmLoggedUser').and.returnValue(of({ email: 'fake-email' }));
+        getBpmLoggedUserSpy = spyOn(authService, 'getBpmLoggedUser').and.returnValue(of({ id: 1001, email: 'fake-email@gmail.com' }));
     });
 
     afterEach(async() => {
@@ -129,22 +130,6 @@ describe('TaskFormComponent', () => {
             expect(formCompletedSpy).toHaveBeenCalled();
         });
 
-        it('Should be able to complete the task as a process initiator', async () => {
-            const formCompletedSpy: jasmine.Spy = spyOn(component.formCompleted, 'emit');
-            const completeTaskFormSpy = spyOn(formService, 'completeTaskForm').and.returnValue(of({}));
-            getTaskDetailsSpy.and.returnValue(of(initiatorCanCompleteTaskDetailsMock));
-            component.taskId = '123';
-            fixture.detectChanges();
-            await fixture.whenStable();
-            const activitFormSelector = element.querySelector('adf-form');
-            const completeButton = fixture.debugElement.nativeElement.querySelector('#adf-form-complete');
-            expect(activitFormSelector).toBeDefined();
-            expect(completeButton['disabled']).toEqual(false);
-            completeButton.click();
-            expect(completeTaskFormSpy).toHaveBeenCalled();
-            expect(formCompletedSpy).toHaveBeenCalled();
-        });
-
         it('Should emit error event in case form complete service fails', async () => {
             const errorSpy: jasmine.Spy = spyOn(component.error, 'emit');
             const completeTaskFormSpy = spyOn(formService, 'completeTaskForm').and.returnValue(throwError({message: 'servce failed'}));
@@ -160,7 +145,6 @@ describe('TaskFormComponent', () => {
             expect(completeTaskFormSpy).toHaveBeenCalled();
             expect(errorSpy).toHaveBeenCalled();
         });
-
     });
 
     describe('change detection', () => {
@@ -500,6 +484,97 @@ describe('TaskFormComponent', () => {
         });
     });
 
+    describe('Complete task', () => {
+
+        it('Should be able to complete the assigned task in case process initiator not allowed to complete the task', async () => {
+            getBpmLoggedUserSpy.and.returnValue(of({ id: 1002, firstName: 'Wilbur', lastName: 'Adams', email: 'wilbur@app.activiti.com' }));
+            getTaskDetailsSpy.and.returnValue(of(taskDetailsMock));
+
+            const formCompletedSpy: jasmine.Spy = spyOn(component.formCompleted, 'emit');
+            const completeTaskFormSpy = spyOn(formService, 'completeTaskForm').and.returnValue(of({}));
+            component.taskId = '123';
+            component.ngOnInit();
+
+            fixture.detectChanges();
+            await fixture.whenStable();
+
+            const completeButton = fixture.debugElement.nativeElement.querySelector('#adf-form-complete');
+
+            expect(component.isProcessInitiator()).toEqual(false);
+            expect(completeButton['disabled']).toEqual(false);
+
+            completeButton.click();
+
+            expect(completeTaskFormSpy).toHaveBeenCalled();
+            expect(formCompletedSpy).toHaveBeenCalled();
+        });
+
+        it('Should be able to complete the task if process initiator allowed to complete the task', async () => {
+            getBpmLoggedUserSpy.and.returnValue(of({ id: 1001, firstName: 'Wilbur', lastName: 'Adams', email: 'wilbur@app.activiti.com' }));
+            const formCompletedSpy: jasmine.Spy = spyOn(component.formCompleted, 'emit');
+            const completeTaskFormSpy = spyOn(formService, 'completeTaskForm').and.returnValue(of({}));
+            getTaskDetailsSpy.and.returnValue(of(initiatorCanCompleteTaskDetailsMock));
+
+            component.taskId = '123';
+            fixture.detectChanges();
+            await fixture.whenStable();
+
+            const activitFormSelector = element.querySelector('adf-form');
+            const completeButton = fixture.debugElement.nativeElement.querySelector('#adf-form-complete');
+
+            expect(activitFormSelector).toBeDefined();
+            expect(completeButton['disabled']).toEqual(false);
+            expect(component.isProcessInitiator()).toEqual(true);
+
+            completeButton.click();
+
+            expect(completeTaskFormSpy).toHaveBeenCalled();
+            expect(formCompletedSpy).toHaveBeenCalled();
+        });
+
+        it('Should not be able to complete a task with candidates users if process initiator allowed to complete the task', async () => {
+            getTaskDetailsSpy.and.returnValue(of(initiatorWithCandidatesTaskDetailsMock));
+
+            component.taskId = '123';
+            fixture.detectChanges();
+            await fixture.whenStable();
+
+            expect(component.canInitiatorComplete()).toEqual(true);
+            expect(component.isProcessInitiator()).toEqual(true);
+            expect(component.isCandidateMember()).toEqual(true);
+
+            const activitFormSelector = element.querySelector('adf-form');
+            const completeButton = fixture.debugElement.nativeElement.querySelector('#adf-form-complete');
+
+            expect(activitFormSelector).toBeDefined();
+            expect(completeButton['disabled']).toEqual(true);
+        });
+
+        it('Should be able to complete a task with candidates users if process initiator not allowed to complete the task', async () => {
+            const formCompletedSpy: jasmine.Spy = spyOn(component.formCompleted, 'emit');
+            getBpmLoggedUserSpy.and.returnValue(of({ id: 1001, firstName: 'Wilbur', lastName: 'Adams', email: 'wilbur@app.activiti.com' }));
+            const completeTaskFormSpy = spyOn(formService, 'completeTaskForm').and.returnValue(of({}));
+            getTaskDetailsSpy.and.returnValue(of(claimedTaskDetailsMock));
+
+            component.taskId = '123';
+            fixture.detectChanges();
+            await fixture.whenStable();
+
+            const activitFormSelector = element.querySelector('adf-form');
+            const completeButton = fixture.debugElement.nativeElement.querySelector('#adf-form-complete');
+
+            expect(activitFormSelector).toBeDefined();
+            expect(component.canInitiatorComplete()).toEqual(false);
+            expect(component.isProcessInitiator()).toEqual(false);
+            expect(completeButton['disabled']).toEqual(false);
+
+            completeButton.click();
+
+            expect(completeTaskFormSpy).toHaveBeenCalled();
+            expect(formCompletedSpy).toHaveBeenCalled();
+        });
+    });
+
     describe('Claim/Unclaim buttons', () => {
 
         it('should display the claim button if no assignee', async() => {
@@ -589,7 +664,7 @@ describe('TaskFormComponent', () => {
 
             component.taskId = 'mock-task-id';
 
-            component.taskClaimed.subscribe((taskId) => {
+            component.taskClaimed.subscribe((taskId: string) => {
                 expect(taskId).toEqual(component.taskId);
                 done();
             });
@@ -601,6 +676,25 @@ describe('TaskFormComponent', () => {
             claimBtn.nativeElement.click();
         });
 
+        it('should emit error event in case claim task api fails', (done) => {
+            const mockError = { message: 'Api Failed' };
+            spyOn(taskListService, 'claimTask').and.returnValue(throwError(mockError));
+            getTaskDetailsSpy.and.returnValue(of(claimableTaskDetailsMock));
+
+            component.taskId = 'mock-task-id';
+
+            component.error.subscribe((error: any) => {
+                expect(error).toEqual(mockError);
+                done();
+            });
+
+            component.ngOnInit();
+            fixture.detectChanges();
+
+            const claimBtn = fixture.debugElement.query(By.css('[adf-claim-task]'));
+            claimBtn.nativeElement.click();
+        });
+
         it('should emit taskUnClaimed when task is unclaimed', (done) => {
             spyOn(taskListService, 'unclaimTask').and.returnValue(of({}));
             getBpmLoggedUserSpy.and.returnValue(of(claimedTaskDetailsMock.assignee));
@@ -619,5 +713,25 @@ describe('TaskFormComponent', () => {
             const unclaimBtn = fixture.debugElement.query(By.css('[adf-unclaim-task]'));
             unclaimBtn.nativeElement.click();
         });
+
+        it('should emit error event in case unclaim task api fails', (done) => {
+            const mockError = { message: 'Api Failed' };
+            spyOn(taskListService, 'unclaimTask').and.returnValue(throwError(mockError));
+            getBpmLoggedUserSpy.and.returnValue(of(claimedTaskDetailsMock.assignee));
+            getTaskDetailsSpy.and.returnValue(of(claimedTaskDetailsMock));
+
+            component.taskId = 'mock-task-id';
+
+            component.error.subscribe((error: any) => {
+                expect(error).toEqual(mockError);
+                done();
+            });
+
+            component.ngOnInit();
+            fixture.detectChanges();
+
+            const unclaimBtn = fixture.debugElement.query(By.css('[adf-unclaim-task]'));
+            unclaimBtn.nativeElement.click();
+        });
     });
 });
diff --git a/lib/process-services/src/lib/task-list/components/task-form/task-form.component.ts b/lib/process-services/src/lib/task-list/components/task-form/task-form.component.ts
index 77dca180fc..dd477fe1a3 100644
--- a/lib/process-services/src/lib/task-list/components/task-form/task-form.component.ts
+++ b/lib/process-services/src/lib/task-list/components/task-form/task-form.component.ts
@@ -272,15 +272,26 @@ export class TaskFormComponent implements OnInit {
   }
 
   isReadOnlyForm(): boolean {
-      return this.internalReadOnlyForm || !(this.isAssignedToMe() || this.canInitiatorComplete());
+    let readOnlyForm: boolean;
+    if (this.isCandidateMember()) {
+      readOnlyForm = this.internalReadOnlyForm || !this.isAssignedToMe();
+    } else {
+      readOnlyForm = this.internalReadOnlyForm || !(this.isAssignedToMe() || (this.canInitiatorComplete() && this.isProcessInitiator()));
+    }
+
+    return readOnlyForm;
+  }
+
+  isProcessInitiator(): boolean {
+    return this.currentLoggedUser && ( this.currentLoggedUser.id === +this.taskDetails.processInstanceStartUserId);
   }
 
   isSaveButtonVisible(): boolean {
     return this.showFormSaveButton && (!this.canInitiatorComplete() || this.isAssignedToMe());
   }
 
-  canCompleteTask(): boolean {
-    return !this.isCompletedTask() && this.isAssignedToMe();
+  canCompleteNoFormTask(): boolean {
+    return this.isReadOnlyForm();
   }
 
   getCompletedTaskTranslatedMessage(): Observable<string> {
@@ -307,7 +318,15 @@ export class TaskFormComponent implements OnInit {
     this.taskClaimed.emit(taskId);
   }
 
+  onClaimTaskError(error: any) {
+    this.error.emit(error);
+  }
+
   onUnclaimTask(taskId: string) {
     this.taskUnclaimed.emit(taskId);
   }
+
+  onUnclaimTaskError(error: any) {
+    this.error.emit(error);
+  }
 }