diff --git a/ui/src/app/applications/components/application-deployment-history/revision-metadata-rows.tsx b/ui/src/app/applications/components/application-deployment-history/revision-metadata-rows.tsx
index 1043d0bfa5659..be141a3b879c4 100644
--- a/ui/src/app/applications/components/application-deployment-history/revision-metadata-rows.tsx
+++ b/ui/src/app/applications/components/application-deployment-history/revision-metadata-rows.tsx
@@ -5,7 +5,7 @@ import {ApplicationSource, RevisionMetadata, ChartDetails} from '../../../shared
 import {services} from '../../../shared/services';
 
 export const RevisionMetadataRows = (props: {applicationName: string; applicationNamespace: string; source: ApplicationSource; index: number; versionId: number}) => {
-    if (props.source.chart) {
+    if (props?.source?.chart) {
         return (
             <DataLoader
                 input={props}
diff --git a/ui/src/app/applications/components/application-details/application-details.tsx b/ui/src/app/applications/components/application-details/application-details.tsx
index 34d5121f87557..5177341bd9d2e 100644
--- a/ui/src/app/applications/components/application-details/application-details.tsx
+++ b/ui/src/app/applications/components/application-details/application-details.tsx
@@ -890,18 +890,20 @@ export class ApplicationDetails extends React.Component<RouteComponentProps<{app
             {
                 iconClassName: 'fa fa-info-circle',
                 title: <ActionMenuItem actionLabel='Details' />,
-                action: () => this.selectNode(fullName)
+                action: () => this.selectNode(fullName),
+                disabled: !app.spec.source
             },
             {
                 iconClassName: 'fa fa-file-medical',
                 title: <ActionMenuItem actionLabel='Diff' />,
                 action: () => this.selectNode(fullName, 0, 'diff'),
-                disabled: app.status.sync.status === appModels.SyncStatuses.Synced
+                disabled: app.status.sync.status === appModels.SyncStatuses.Synced || !app.spec.source
             },
             {
                 iconClassName: 'fa fa-sync',
                 title: <ActionMenuItem actionLabel='Sync' />,
-                action: () => AppUtils.showDeploy('all', null, this.appContext.apis)
+                action: () => AppUtils.showDeploy('all', null, this.appContext.apis),
+                disabled: !app.spec.source
             },
             {
                 iconClassName: 'fa fa-info-circle',
diff --git a/ui/src/app/applications/components/application-parameters/application-parameters.tsx b/ui/src/app/applications/components/application-parameters/application-parameters.tsx
index 427be982b05f6..78f026ff0759b 100644
--- a/ui/src/app/applications/components/application-parameters/application-parameters.tsx
+++ b/ui/src/app/applications/components/application-parameters/application-parameters.tsx
@@ -556,23 +556,24 @@ function gatherCoreSourceDetails(i: number, attributes: EditablePanelItem[], sou
                 )
             });
         } else {
+            const targetRevision = source ? source.targetRevision || 'HEAD' : 'Unknown';
             attributes.push({
                 title: 'TARGET REVISION',
-                view: <Revision repoUrl={source.repoURL} revision={source.targetRevision || 'HEAD'} />,
-                edit: (formApi: FormApi) => <RevisionFormField helpIconTop={'0'} hideLabel={true} formApi={formApi} repoURL={source.repoURL} fieldValue={revisionField} />
+                view: <Revision repoUrl={source?.repoURL} revision={targetRevision} />,
+                edit: (formApi: FormApi) => <RevisionFormField helpIconTop={'0'} hideLabel={true} formApi={formApi} repoURL={source?.repoURL} fieldValue={revisionField} />
             });
             attributes.push({
                 title: 'PATH',
                 view: (
-                    <Revision repoUrl={source.repoURL} revision={source.targetRevision || 'HEAD'} path={source.path} isForPath={true}>
-                        {processPath(source.path)}
+                    <Revision repoUrl={source?.repoURL} revision={targetRevision} path={source?.path} isForPath={true}>
+                        {processPath(source?.path)}
                     </Revision>
                 ),
                 edit: (formApi: FormApi) => <FormField formApi={formApi} field={sourcesPathField} component={Text} />
             });
             attributes.push({
                 title: 'REF',
-                view: <span>{source.ref}</span>,
+                view: <span>{source?.ref}</span>,
                 edit: (formApi: FormApi) => <FormField formApi={formApi} field={refField} component={Text} />
             });
         }
diff --git a/ui/src/app/applications/components/application-status-panel/application-status-panel.tsx b/ui/src/app/applications/components/application-status-panel/application-status-panel.tsx
index 643e24034d54a..ee76418546a4e 100644
--- a/ui/src/app/applications/components/application-status-panel/application-status-panel.tsx
+++ b/ui/src/app/applications/components/application-status-panel/application-status-panel.tsx
@@ -112,7 +112,7 @@ export const ApplicationStatusPanel = ({application, showDiff, showOperation, sh
                         application.status.sync &&
                         (hasMultipleSources
                             ? application.status.sync.revisions && application.status.sync.revisions[0] && application.spec.sources && !application.spec.sources[0].chart
-                            : application.status.sync.revision && !application.spec.source.chart) && (
+                            : application.status.sync.revision && !application.spec?.source?.chart) && (
                             <div className='application-status-panel__item-name'>
                                 <RevisionMetadataPanel
                                     appName={application.metadata.name}
@@ -160,7 +160,7 @@ export const ApplicationStatusPanel = ({application, showDiff, showOperation, sh
                             <RevisionMetadataPanel
                                 appName={application.metadata.name}
                                 appNamespace={application.metadata.namespace}
-                                type={source.chart && 'helm'}
+                                type={source?.chart && 'helm'}
                                 revision={operationStateRevision}
                                 versionId={utils.getAppCurrentVersion(application)}
                             />
diff --git a/ui/src/app/applications/components/application-summary/application-summary.tsx b/ui/src/app/applications/components/application-summary/application-summary.tsx
index 1747e943af69f..af98824f97b7b 100644
--- a/ui/src/app/applications/components/application-summary/application-summary.tsx
+++ b/ui/src/app/applications/components/application-summary/application-summary.tsx
@@ -172,7 +172,7 @@ export const ApplicationSummary = (props: ApplicationSummaryProps) => {
         },
         !hasMultipleSources && {
             title: 'REPO URL',
-            view: <Repo url={source.repoURL} />,
+            view: <Repo url={source?.repoURL} />,
             edit: (formApi: FormApi) => <FormField formApi={formApi} field='spec.source.repoURL' component={Text} />
         },
         ...(!hasMultipleSources
@@ -180,11 +180,7 @@ export const ApplicationSummary = (props: ApplicationSummaryProps) => {
                 ? [
                       {
                           title: 'CHART',
-                          view: (
-                              <span>
-                                  {source.chart}:{source.targetRevision}
-                              </span>
-                          ),
+                          view: <span>{source && `${source.chart}:${source.targetRevision}`}</span>,
                           edit: (formApi: FormApi) =>
                               hasMultipleSources ? (
                                   helpTip('CHART is not editable for applications with multiple sources. You can edit them in the "Manifest" tab.')
diff --git a/ui/src/app/applications/components/applications-list/applications-source.tsx b/ui/src/app/applications/components/applications-list/applications-source.tsx
index 0a5fbe51f37c0..d0fe9d096444a 100644
--- a/ui/src/app/applications/components/applications-list/applications-source.tsx
+++ b/ui/src/app/applications/components/applications-list/applications-source.tsx
@@ -5,7 +5,7 @@ import {ApplicationSource as ApplicationSourceType} from '../../../shared/models
 import './applications-source.scss';
 
 export const ApplicationsSource = ({source}: {source: ApplicationSourceType}) => {
-    const sourceString = `${source.repoURL}/${source.path || source.chart}`;
+    const sourceString = source ? `${source.repoURL}/${source.path || source.chart}` : '';
     return (
         <Tooltip content={sourceString}>
             <div className='application-source'>{sourceString}</div>
diff --git a/ui/src/app/applications/components/applications-list/applications-tiles.tsx b/ui/src/app/applications/components/applications-list/applications-tiles.tsx
index 3467d3b952a87..0c6f63b66e460 100644
--- a/ui/src/app/applications/components/applications-list/applications-tiles.tsx
+++ b/ui/src/app/applications/components/applications-list/applications-tiles.tsx
@@ -108,6 +108,7 @@ export const ApplicationTiles = ({applications, syncApplication, refreshApplicat
                             <div className='applications-tiles argo-table-list argo-table-list--clickable' ref={appContainerRef}>
                                 {applications.map((app, i) => {
                                     const source = getAppDefaultSource(app);
+                                    const targetRevision = source ? source.targetRevision || 'HEAD' : 'Unknown';
                                     return (
                                         <div
                                             key={AppUtils.appInstanceName(app)}
@@ -126,7 +127,7 @@ export const ApplicationTiles = ({applications, syncApplication, refreshApplicat
                                                     )} applications-tiles__item`}>
                                                     <div className='row '>
                                                         <div className={app.status.summary.externalURLs?.length > 0 ? 'columns small-10' : 'columns small-11'}>
-                                                            <i className={'icon argo-icon-' + (source.chart != null ? 'helm' : 'git')} />
+                                                            <i className={'icon argo-icon-' + (source?.chart != null ? 'helm' : 'git')} />
                                                             <Tooltip content={AppUtils.appInstanceName(app)}>
                                                                 <span className='applications-list__title'>
                                                                     {AppUtils.appQualifiedName(app, useAuthSettingsCtx?.appsInAnyNamespaceEnabled)}
@@ -208,8 +209,8 @@ export const ApplicationTiles = ({applications, syncApplication, refreshApplicat
                                                             Repository:
                                                         </div>
                                                         <div className='columns small-9'>
-                                                            <Tooltip content={source.repoURL} zIndex={4}>
-                                                                <span>{source.repoURL}</span>
+                                                            <Tooltip content={source?.repoURL} zIndex={4}>
+                                                                <span>{source?.repoURL}</span>
                                                             </Tooltip>
                                                         </div>
                                                     </div>
@@ -217,22 +218,22 @@ export const ApplicationTiles = ({applications, syncApplication, refreshApplicat
                                                         <div className='columns small-3' title='Target Revision:'>
                                                             Target Revision:
                                                         </div>
-                                                        <div className='columns small-9'>{source.targetRevision || 'HEAD'}</div>
+                                                        <div className='columns small-9'>{targetRevision}</div>
                                                     </div>
-                                                    {source.path && (
+                                                    {source?.path && (
                                                         <div className='row'>
                                                             <div className='columns small-3' title='Path:'>
                                                                 Path:
                                                             </div>
-                                                            <div className='columns small-9'>{source.path}</div>
+                                                            <div className='columns small-9'>{source?.path}</div>
                                                         </div>
                                                     )}
-                                                    {source.chart && (
+                                                    {source?.chart && (
                                                         <div className='row'>
                                                             <div className='columns small-3' title='Chart:'>
                                                                 Chart:
                                                             </div>
-                                                            <div className='columns small-9'>{source.chart}</div>
+                                                            <div className='columns small-9'>{source?.chart}</div>
                                                         </div>
                                                     )}
                                                     <div className='row'>
diff --git a/ui/src/app/applications/components/utils.tsx b/ui/src/app/applications/components/utils.tsx
index e4625bde7c9d4..d660242d2196d 100644
--- a/ui/src/app/applications/components/utils.tsx
+++ b/ui/src/app/applications/components/utils.tsx
@@ -706,10 +706,10 @@ export function renderResourceButtons(
 export function syncStatusMessage(app: appModels.Application) {
     const source = getAppDefaultSource(app);
     const revision = getAppDefaultSyncRevision(app);
-    const rev = app.status.sync.revision || source.targetRevision || 'HEAD';
-    let message = source.targetRevision || 'HEAD';
+    const rev = app.status.sync.revision || (source ? source.targetRevision || 'HEAD' : 'Unknown');
+    let message = source ? source?.targetRevision || 'HEAD' : 'Unknown';
 
-    if (revision) {
+    if (revision && source) {
         if (source.chart) {
             message += ' (' + revision + ')';
         } else if (revision.length >= 7 && !revision.startsWith(source.targetRevision)) {
@@ -1080,7 +1080,7 @@ export const getPodReadinessGatesState = (pod: appModels.State): {nonExistingCon
     for (const condition of podStatusConditions) {
         existingConditions.set(condition.type, true);
         // priority order of conditions
-        // eg. if there are multiple conditions set with same name then the one which comes first is evaluated
+        // e.g. if there are multiple conditions set with same name then the one which comes first is evaluated
         if (podConditions.has(condition.type)) {
             continue;
         }
@@ -1127,10 +1127,10 @@ export function isAppNode(node: appModels.ResourceNode) {
 
 export function getAppOverridesCount(app: appModels.Application) {
     const source = getAppDefaultSource(app);
-    if (source.kustomize && source.kustomize.images) {
+    if (source?.kustomize?.images) {
         return source.kustomize.images.length;
     }
-    if (source.helm && source.helm.parameters) {
+    if (source?.helm?.parameters) {
         return source.helm.parameters.length;
     }
     return 0;