diff --git a/webapp/js/layout/Header.vue b/webapp/js/layout/Header.vue
index 0cc85a5..c7711ba 100644
--- a/webapp/js/layout/Header.vue
+++ b/webapp/js/layout/Header.vue
@@ -16,7 +16,7 @@
                 <i class="fa-solid fa-sitemap"></i>
             </Button>
             <Button v-if="showDownload" @click="handleDownload" severity="secondary" size="small" text
-                :title="selectedFiles.length > 0 ? `Download ${selectedFiles.length} file${selectedFiles.length !== 1 ? 's' : ''}` : 'Download'" :disabled="isDownloading">
+                :title="downloadTitle" :disabled="isDownloading || downloadBlocked">
                 <i class="fa-solid fa-download"></i>
                 <span v-if="selectedFiles.length > 0" style="line-height: 1;" class="ms-1">{{ selectedFiles.length }}</span>
             </Button>
@@ -84,7 +84,7 @@
 </template>
 
 <script>
-import { utils } from 'ddb';
+import ddb, { utils } from 'ddb';
 import reg from '@/libs/api/sharedRegistry';
 import { Features } from '@/libs/features';
 import Alert from '@/components/Alert';
@@ -224,6 +224,25 @@ export default {
             }
             return 'Are you sure you want to download the entire dataset?';
         },
+        downloadIsBulk: function () {
+            // Whole-dataset download or multi-file selection is always bulk.
+            if (this.selectedFiles.length !== 1) return true;
+            const sel = this.selectedFiles[0];
+            // Single selection counts as bulk only when it is a directory.
+            if (sel && sel.entry) return ddb.entry.isDirectory(sel.entry);
+            // Conservative fallback: treat as bulk when entry metadata is missing.
+            return true;
+        },
+        downloadBlocked: function () {
+            return !this.loggedIn
+                && reg.getFeature(Features.DISABLE_ANONYMOUS_BULK_DOWNLOADS)
+                && this.downloadIsBulk;
+        },
+        downloadTitle: function () {
+            if (this.downloadBlocked) return 'Login required to download multiple files or the entire dataset';
+            if (this.selectedFiles.length > 0) return `Download ${this.selectedFiles.length} file${this.selectedFiles.length !== 1 ? 's' : ''}`;
+            return 'Download';
+        },
         userMenuItems: function () {
             const items = [];
 
diff --git a/webapp/js/libs/contextMenuItems.js b/webapp/js/libs/contextMenuItems.js
index 1811201..ff56b36 100644
--- a/webapp/js/libs/contextMenuItems.js
+++ b/webapp/js/libs/contextMenuItems.js
@@ -183,11 +183,27 @@ function shareEmbedItem(ctx) {
 }
 
 function downloadItem(ctx) {
+    const isBulkSelection = () => {
+        const sel = ctx.getSelectedEntries();
+        if (sel.length === 0) return false;
+        if (sel.length > 1) return true;
+        // single selection: bulk if it's a directory
+        return ddb.entry.isDirectory(sel[0].entry);
+    };
+    const isBulkBlocked = () =>
+        !reg.isLoggedIn() &&
+        reg.getFeature(Features.DISABLE_ANONYMOUS_BULK_DOWNLOADS) &&
+        isBulkSelection();
+
     return {
         label: 'Download',
         icon: 'fa-solid fa-download',
         isVisible: () => ctx.getSelectedEntries().length > 0,
-        click: () => ctx.emit('downloadItems', ctx.getSelectedEntries())
+        isEnabled: () => !isBulkBlocked(),
+        click: () => {
+            if (isBulkBlocked()) return;
+            ctx.emit('downloadItems', ctx.getSelectedEntries());
+        }
     };
 }
 
diff --git a/webapp/js/libs/features.js b/webapp/js/libs/features.js
index 67ff670..2893cf8 100644
--- a/webapp/js/libs/features.js
+++ b/webapp/js/libs/features.js
@@ -8,5 +8,6 @@ export const Features = {
     STORAGE_LIMITER: 'storageLimiter',
     PASSWORD_POLICY: 'passwordPolicy',
     DATASET_THUMBNAIL_CANDIDATES: 'datasetThumbnailCandidates',
-    MAX_EXPORT_SIZE_BYTES: 'maxExportSizeBytes'
+    MAX_EXPORT_SIZE_BYTES: 'maxExportSizeBytes',
+    DISABLE_ANONYMOUS_BULK_DOWNLOADS: 'disableAnonymousBulkDownloads'
 };