diff --git a/client/src/app/site/projector/services/projector-data.service.spec.ts b/client/src/app/core/core-services/projector-data.service.spec.ts
similarity index 87%
rename from client/src/app/site/projector/services/projector-data.service.spec.ts
rename to client/src/app/core/core-services/projector-data.service.spec.ts
index 80cfc4aeb..2af4f63ba 100644
--- a/client/src/app/site/projector/services/projector-data.service.spec.ts
+++ b/client/src/app/core/core-services/projector-data.service.spec.ts
@@ -1,5 +1,5 @@
 import { TestBed, inject } from '@angular/core/testing';
-import { E2EImportsModule } from '../../../../e2e-imports.module';
+import { E2EImportsModule } from '../../../e2e-imports.module';
 import { ProjectorDataService } from './projector-data.service';
 
 describe('ProjectorDataService', () => {
diff --git a/client/src/app/site/projector/services/projector-data.service.ts b/client/src/app/core/core-services/projector-data.service.ts
similarity index 79%
rename from client/src/app/site/projector/services/projector-data.service.ts
rename to client/src/app/core/core-services/projector-data.service.ts
index 4d3eafb95..21ebc7a2f 100644
--- a/client/src/app/site/projector/services/projector-data.service.ts
+++ b/client/src/app/core/core-services/projector-data.service.ts
@@ -1,9 +1,11 @@
 import { Injectable } from '@angular/core';
-import { WebsocketService } from 'app/core/core-services/websocket.service';
-import { Observable, BehaviorSubject } from 'rxjs';
-import { ProjectorElement } from 'app/shared/models/core/projector';
 
-export interface SlideData<T = object> {
+import { Observable, BehaviorSubject } from 'rxjs';
+
+import { WebsocketService } from 'app/core/core-services/websocket.service';
+import { ProjectorElement, Projector } from 'app/shared/models/core/projector';
+
+export interface SlideData<T = { error?: string }> {
     data: T;
     element: ProjectorElement;
     error?: string;
@@ -40,21 +42,16 @@ export class ProjectorDataService {
      * @param websocketService
      */
     public constructor(private websocketService: WebsocketService) {
-        // TODO: On reconnect, we do need to re-inform the server about all needed projectors. This also
-        // updates our projector data, which is great!
         this.websocketService.getOberservable('projector').subscribe((update: AllProjectorData) => {
             Object.keys(update).forEach(_id => {
                 const id = parseInt(_id, 10);
-                if ((<{ error: string }>update[id]).error !== undefined) {
-                    console.log(update, update[_id]);
-                    console.log('TODO: Why does the server sends errors on autoupdates?');
-                } else {
-                    if (this.currentProjectorData[id]) {
-                        this.currentProjectorData[id].next(update[id] as ProjectorData);
-                    }
+                if (this.currentProjectorData[id]) {
+                    this.currentProjectorData[id].next(update[id] as ProjectorData);
                 }
             });
         });
+
+        this.websocketService.reconnectEvent.subscribe(() => this.updateProjectorDataSubscription());
     }
 
     /**
@@ -105,4 +102,15 @@ export class ProjectorDataService {
             .filter(id => this.openProjectorInstances[id] > 0);
         this.websocketService.send('listenToProjectors', { projector_ids: allActiveProjectorIds });
     }
+
+    /**
+     * @returns the available projectior data for the given projector. Note that the data
+     * might not be there, if there is no subscribtion for this projector. But the
+     * data, if exist, is always the current data.
+     */
+    public getAvailableProjectorData(projector: Projector): ProjectorData | null {
+        if (this.currentProjectorData[projector.id]) {
+            return this.currentProjectorData[projector.id].getValue();
+        }
+    }
 }
diff --git a/client/src/app/core/core-services/projector.service.ts b/client/src/app/core/core-services/projector.service.ts
index b57f795fe..0a4ee7931 100644
--- a/client/src/app/core/core-services/projector.service.ts
+++ b/client/src/app/core/core-services/projector.service.ts
@@ -1,5 +1,7 @@
 import { Injectable } from '@angular/core';
 
+import { TranslateService } from '@ngx-translate/core';
+
 import {
     Projectable,
     ProjectorElementBuildDeskriptor,
@@ -11,15 +13,16 @@ import {
     Projector,
     ProjectorElement,
     ProjectorElements,
-    IdentifiableProjectorElement
+    IdentifiableProjectorElement,
+    elementIdentifies
 } from 'app/shared/models/core/projector';
 import { HttpService } from './http.service';
 import { SlideManager } from 'app/slides/services/slide-manager.service';
 import { BaseModel } from 'app/shared/models/base/base-model';
 import { ViewModelStoreService } from './view-model-store.service';
 import { BaseProjectableViewModel } from 'app/site/base/base-projectable-view-model';
-import { TranslateService } from '@ngx-translate/core';
 import { ConfigService } from '../ui-services/config.service';
+import { ProjectorDataService } from './projector-data.service';
 
 /**
  * This service cares about Projectables being projected and manage all projection-related
@@ -43,7 +46,8 @@ export class ProjectorService {
         private slideManager: SlideManager,
         private viewModelStore: ViewModelStoreService,
         private translate: TranslateService,
-        private configService: ConfigService
+        private configService: ConfigService,
+        private projectorDataService: ProjectorDataService
     ) {}
 
     /**
@@ -201,7 +205,7 @@ export class ProjectorService {
     ): Promise<void> {
         const requestData: any = {};
         if (elements) {
-            requestData.elements = elements;
+            requestData.elements = this.cleanupElements(projector, elements);
         }
         if (preview) {
             requestData.preview = preview;
@@ -218,6 +222,31 @@ export class ProjectorService {
         await this.http.post(`/rest/core/projector/${projector.id}/project/`, requestData);
     }
 
+    /**
+     * Cleans up stable elements with errors from the projector
+     *
+     * @param projector The projector
+     * @param elements The elements to clean up
+     * @reutns the cleaned up elements.
+     */
+    private cleanupElements(projector: Projector, elements: ProjectorElements): ProjectorElements {
+        const projectorData = this.projectorDataService.getAvailableProjectorData(projector);
+
+        if (projectorData) {
+            projectorData.forEach(entry => {
+                if (entry.data.error && entry.element.stable) {
+                    // Remove this element
+                    const idElementToRemove = this.slideManager.getIdentifialbeProjectorElement(entry.element);
+                    elements = elements.filter(element => {
+                        return !elementIdentifies(idElementToRemove, element);
+                    });
+                }
+            });
+        }
+
+        return elements;
+    }
+
     /**
      * Given a projectiondefault, we want to retrieve the projector, that is assigned
      * to this default.
diff --git a/client/src/app/shared/components/projector/projector.component.ts b/client/src/app/shared/components/projector/projector.component.ts
index ac6e05079..c0f1fe341 100644
--- a/client/src/app/shared/components/projector/projector.component.ts
+++ b/client/src/app/shared/components/projector/projector.component.ts
@@ -8,7 +8,7 @@ import { BaseComponent } from 'app/base.component';
 import { ConfigService } from 'app/core/ui-services/config.service';
 import { ViewProjector } from 'app/site/projector/models/view-projector';
 import { Size } from 'app/site/projector/size';
-import { SlideData, ProjectorDataService } from 'app/site/projector/services/projector-data.service';
+import { SlideData, ProjectorDataService } from 'app/core/core-services/projector-data.service';
 import { ProjectorRepositoryService } from 'app/core/repositories/projector/projector-repository.service';
 
 /**
diff --git a/client/src/app/shared/components/slide-container/slide-container.component.ts b/client/src/app/shared/components/slide-container/slide-container.component.ts
index 276070582..94b7057f0 100644
--- a/client/src/app/shared/components/slide-container/slide-container.component.ts
+++ b/client/src/app/shared/components/slide-container/slide-container.component.ts
@@ -5,7 +5,7 @@ import { TranslateService } from '@ngx-translate/core';
 import { BaseComponent } from 'app/base.component';
 import { SlideManager } from 'app/slides/services/slide-manager.service';
 import { BaseSlideComponent } from 'app/slides/base-slide-component';
-import { SlideData } from 'app/site/projector/services/projector-data.service';
+import { SlideData } from 'app/core/core-services/projector-data.service';
 import { ProjectorElement } from 'app/shared/models/core/projector';
 import { ViewProjector } from 'app/site/projector/models/view-projector';
 
diff --git a/client/src/app/shared/models/core/projector.ts b/client/src/app/shared/models/core/projector.ts
index 87f523cad..aa970f1fc 100644
--- a/client/src/app/shared/models/core/projector.ts
+++ b/client/src/app/shared/models/core/projector.ts
@@ -29,6 +29,19 @@ export interface IdentifiableProjectorElement extends ProjectorElement {
     getIdentifiers(): (keyof IdentifiableProjectorElement)[];
 }
 
+/**
+ * Compares an identifiable element to an element. Every identifier of `a` must match, if
+ * the attribute is given in the element `b`.
+ *
+ * @param a The identifiable element
+ * @param b The non-identifiable element
+ */
+export function elementIdentifies(a: IdentifiableProjectorElement, b: ProjectorElement): boolean {
+    return a.getIdentifiers().every(identifier => {
+        return !b[identifier] || b[identifier] === a[identifier];
+    });
+}
+
 /**
  * Multiple elements.
  */
@@ -128,14 +141,24 @@ export class Projector extends BaseModel<Projector> {
         let removedElements: ProjectorElements;
         let nonRemovedElements: ProjectorElements;
         [removedElements, nonRemovedElements] = this.partitionArray(this.elements, elementOnProjector => {
-            return element.getIdentifiers().every(identifier => {
-                return !elementOnProjector[identifier] || elementOnProjector[identifier] === element[identifier];
-            });
+            return elementIdentifies(element, elementOnProjector);
         });
         this.elements = nonRemovedElements;
         return removedElements;
     }
 
+    /**
+     * Replaces all elements with the given elements, if these elements can identify to the
+     * given one.
+     *
+     * @param element The element to replace
+     */
+    public replaceElements(element: IdentifiableProjectorElement): void {
+        this.elements = this.elements.map(elementOnProjector =>
+            elementIdentifies(element, elementOnProjector) ? element : elementOnProjector
+        );
+    }
+
     /**
      * Splits up the array into two arrays. All elements with a true return value from the callback
      * will be in the fist array, all others in the second one.
diff --git a/client/src/app/site/projector/projector.module.ts b/client/src/app/site/projector/projector.module.ts
index 6f4eb3833..571490314 100644
--- a/client/src/app/site/projector/projector.module.ts
+++ b/client/src/app/site/projector/projector.module.ts
@@ -5,15 +5,11 @@ import { ProjectorRoutingModule } from './projector-routing.module';
 import { SharedModule } from '../../shared/shared.module';
 import { ProjectorListComponent } from './components/projector-list/projector-list.component';
 import { ProjectorDetailComponent } from './components/projector-detail/projector-detail.component';
-import { ClockSlideService } from './services/clock-slide.service';
-import { ProjectorDataService } from './services/projector-data.service';
-import { CurrentListOfSpeakersSlideService } from './services/current-list-of-of-speakers-slide.service';
 import { CountdownListComponent } from './components/countdown-list/countdown-list.component';
 import { ProjectorMessageListComponent } from './components/projector-message-list/projector-message-list.component';
 import { CountdownControlsComponent } from './components/countdown-controls/countdown-controls.component';
 
 @NgModule({
-    providers: [ClockSlideService, ProjectorDataService, CurrentListOfSpeakersSlideService],
     imports: [CommonModule, ProjectorRoutingModule, SharedModule],
     declarations: [
         ProjectorListComponent,
diff --git a/client/src/app/slides/base-slide-component.ts b/client/src/app/slides/base-slide-component.ts
index 15bc149af..29d1e2eec 100644
--- a/client/src/app/slides/base-slide-component.ts
+++ b/client/src/app/slides/base-slide-component.ts
@@ -1,6 +1,7 @@
 import { Input } from '@angular/core';
-import { SlideData } from 'app/site/projector/services/projector-data.service';
+
 import { ViewProjector } from 'app/site/projector/models/view-projector';
+import { SlideData } from 'app/core/core-services/projector-data.service';
 
 /**
  * Every slide has to extends this base class. It forces the slides
diff --git a/client/src/app/slides/motions/motion/motion-slide.component.ts b/client/src/app/slides/motions/motion/motion-slide.component.ts
index de3821783..06bb8c4dc 100644
--- a/client/src/app/slides/motions/motion/motion-slide.component.ts
+++ b/client/src/app/slides/motions/motion/motion-slide.component.ts
@@ -8,7 +8,7 @@ import { DiffLinesInParagraph, DiffService, LineRange } from '../../../core/ui-s
 import { LinenumberingService } from '../../../core/ui-services/linenumbering.service';
 import { ViewUnifiedChange } from '../../../shared/models/motions/view-unified-change';
 import { MotionSlideObjChangeReco } from './motion-slide-obj-change-reco';
-import { SlideData } from '../../../site/projector/services/projector-data.service';
+import { SlideData } from '../../../core/core-services/projector-data.service';
 import { MotionSlideObjAmendmentParagraph } from './motion-slide-obj-amendment-paragraph';
 
 @Component({