diff --git a/src/app/project/beta/ontology-classes/ontology-class-instance/ontology-class-instance.component.ts b/src/app/project/beta/ontology-classes/ontology-class-instance/ontology-class-instance.component.ts
index 342e90d19f..89237c3a12 100644
--- a/src/app/project/beta/ontology-classes/ontology-class-instance/ontology-class-instance.component.ts
+++ b/src/app/project/beta/ontology-classes/ontology-class-instance/ontology-class-instance.component.ts
@@ -87,7 +87,8 @@ export class OntologyClassInstanceComponent implements OnChanges {
                 // find ontology of current resource class to get the class label
                 const classes = ontologies[ontologies.findIndex(onto => onto.id === this.ontoId)].getAllClassDefinitions();
                 this.resClass = <ResourceClassDefinition>classes[classes.findIndex(res => res.id === this.classId)];
-            }
+            },
+            () => {} // don't log error to rollbar if 'currentProjectOntologies' does not exist in the cache
         );
     }
 
diff --git a/src/app/project/ontology/ontology-form/ontology-form.component.ts b/src/app/project/ontology/ontology-form/ontology-form.component.ts
index 07ef0e5a20..2f5b542064 100644
--- a/src/app/project/ontology/ontology-form/ontology-form.component.ts
+++ b/src/app/project/ontology/ontology-form/ontology-form.component.ts
@@ -138,7 +138,8 @@ export class OntologyFormComponent implements OnInit {
                         const name = this._ontologyService.getOntologyName(onto.id);
                         this.existingOntologyNames.push(name);
                     });
-                }
+                },
+                () => {} // don't log error to rollbar if 'currentProjectOntologies' does not exist in the cache
             );
         }
 
diff --git a/src/app/project/ontology/ontology.component.ts b/src/app/project/ontology/ontology.component.ts
index 0f0c10a4de..3625b9356f 100644
--- a/src/app/project/ontology/ontology.component.ts
+++ b/src/app/project/ontology/ontology.component.ts
@@ -383,7 +383,8 @@ export class OntologyComponent implements OnInit {
                 // update current list of project ontologies
                 ontologies[ontologies.findIndex(onto => onto.id === ontology.id)] = ontology;
                 this._cache.set('currentProjectOntologies', ontologies);
-            }
+            },
+            () => {} // don't log error to rollbar if 'currentProjectOntologies' does not exist in the cache
         );
 
         // grab the onto class information to display
diff --git a/src/app/project/ontology/ontology.service.ts b/src/app/project/ontology/ontology.service.ts
index cd09e069de..9842e5745c 100644
--- a/src/app/project/ontology/ontology.service.ts
+++ b/src/app/project/ontology/ontology.service.ts
@@ -116,7 +116,8 @@ export class OntologyService {
                         (ontologies: ReadOntology[]) => {
                             const onto = ontologies.find(i => i.id === baseOntoIri);
                             superPropIri = onto.properties[subProp].subPropertyOf[0];
-                        }
+                        },
+                        () => {} // don't log error to rollbar if 'currentProjectOntologies' does not exist in the cache
                     );
                 }
 
diff --git a/src/app/project/ontology/property-form/property-form.component.ts b/src/app/project/ontology/property-form/property-form.component.ts
index 472860f263..148721fb9f 100644
--- a/src/app/project/ontology/property-form/property-form.component.ts
+++ b/src/app/project/ontology/property-form/property-form.component.ts
@@ -191,7 +191,8 @@ export class PropertyFormComponent implements OnInit {
                         this.ontologyClasses.push(ontoClasses);
                     }
                 });
-            }
+            },
+            () => {} // don't log error to rollbar if 'currentProjectOntologies' does not exist in the cache
         );
 
         // b) in case of list value:
diff --git a/src/app/project/ontology/property-info/property-info.component.ts b/src/app/project/ontology/property-info/property-info.component.ts
index ce137dd520..97d0f40e3d 100644
--- a/src/app/project/ontology/property-info/property-info.component.ts
+++ b/src/app/project/ontology/property-info/property-info.component.ts
@@ -214,7 +214,8 @@ export class PropertyInfoComponent implements OnChanges, AfterContentInit {
                             this.propAttribute = onto.classes[this.propDef.objectType].label;
                             this.propAttributeComment = onto.classes[this.propDef.objectType].comment;
                         }
-                    }
+                    },
+                    () => {} // don't log error to rollbar if 'currentProjectOntologies' does not exist in the cache
                 );
             } else {
                 this.propAttribute = this.ontology.classes[this.propDef.objectType].label;
@@ -256,7 +257,8 @@ export class PropertyInfoComponent implements OnChanges, AfterContentInit {
                             }
                         });
                     });
-                }
+                },
+                () => {} // don't log error to rollbar if 'currentProjectOntologies' does not exist in the cache
             );
         }
     }
diff --git a/src/app/project/ontology/resource-class-info/resource-class-info.component.ts b/src/app/project/ontology/resource-class-info/resource-class-info.component.ts
index aacd84e222..3636ba4569 100644
--- a/src/app/project/ontology/resource-class-info/resource-class-info.component.ts
+++ b/src/app/project/ontology/resource-class-info/resource-class-info.component.ts
@@ -124,7 +124,8 @@ export class ResourceClassInfoComponent implements OnInit {
                     };
                     this.ontoProperties.push(prepareList);
                 });
-            }
+            },
+            () => {} // don't log error to rollbar if 'currentProjectOntologies' does not exist in the cache
         );
 
         // get currently selected ontology
diff --git a/src/app/project/project.component.html b/src/app/project/project.component.html
index 2569ba63e2..5b578b2035 100644
--- a/src/app/project/project.component.html
+++ b/src/app/project/project.component.html
@@ -18,7 +18,7 @@
         <mat-sidenav-container class="project-view">
             <mat-sidenav mode="side" opened class="project-nav">
                 <!-- Project label -->
-                <div class="link project-title" [routerLink]="'/beta/project/' + project.shortcode">
+                <div *ngIf="project !== undefined" class="link project-title" [routerLink]="'/beta/project/' + project.shortcode">
                     <p #projectTitle matTooltip="{{project.longname}}" matTooltipShowDelay="500"
                         [matTooltipDisabled]="compareElementHeights(projectTitle)" matTooltipPosition="right">
                         {{project.longname}}
diff --git a/src/app/workspace/resource/resource.component.html b/src/app/workspace/resource/resource.component.html
index a117f106a3..fd323cc33f 100644
--- a/src/app/workspace/resource/resource.component.html
+++ b/src/app/workspace/resource/resource.component.html
@@ -2,7 +2,7 @@
     <div class="resource-view" *ngIf="resource">
 
         <!-- dsp-resource-representation -->
-        <div class="representation-container center" *ngIf="representationsToDisplay.length && representationsToDisplay[0].fileValue"
+        <div class="representation-container center" *ngIf="representationsToDisplay?.length && representationsToDisplay[0].fileValue"
             [ngSwitch]="representationsToDisplay[0].fileValue?.type">
             <!-- still image view -->
             <app-still-image #stillImage class="dsp-representation stillimage" *ngSwitchCase="representationConstants.stillImage"
@@ -88,7 +88,7 @@
 
                 <!-- annotations -->
                 <mat-tab label="annotations"
-                    *ngIf="representationsToDisplay.length && representationsToDisplay[0].fileValue && representationsToDisplay[0].fileValue.type === representationConstants.stillImage">
+                    *ngIf="representationsToDisplay?.length && representationsToDisplay[0].fileValue && representationsToDisplay[0].fileValue.type === representationConstants.stillImage">
                     <ng-template matTabLabel class="annotations">
                         <span [matBadge]="representationsToDisplay[0]?.annotations.length"
                             [matBadgeHidden]="representationsToDisplay[0]?.annotations.length === 0" matBadgeColor="primary"
diff --git a/src/app/workspace/results/results.component.ts b/src/app/workspace/results/results.component.ts
index 19a40e302b..ac22c566d0 100644
--- a/src/app/workspace/results/results.component.ts
+++ b/src/app/workspace/results/results.component.ts
@@ -63,7 +63,7 @@ export class ResultsComponent {
 
     onSelectionChange(res: FilteredResources) {
         this.selectedResources = res;
-        this.resourceIri = this.selectedResources.resInfo[0].id;
+        this.resourceIri = this.selectedResources.resInfo[0]?.id;
 
         if (!res || res.count <= 1) {
             this.viewMode = 'single';