diff --git a/frontend/src/lib/api/endpoints/admin.ts b/frontend/src/lib/api/endpoints/admin.ts
index dda24e49..c74da06e 100644
--- a/frontend/src/lib/api/endpoints/admin.ts
+++ b/frontend/src/lib/api/endpoints/admin.ts
@@ -199,6 +199,48 @@ export function listUsers(limit: number, offset: number): Promise<AdminUsersPage
 	});
 }
 
+/**
+ * Admin-scoped single-user lookup — `GET /api/admin/users/{id}`.
+ * Returns the full `User` DTO including `storage_quota_bytes` +
+ * `storage_used_bytes` which the non-admin `/api/users/{id}`
+ * response omits for privacy.
+ *
+ * Result promises are cached per id at module scope so multiple
+ * callers for the same user (e.g. the admin drives table with N
+ * personal drives owned by the same person) share one fetch. A
+ * `null` result is cached too so a missing user isn't re-fetched
+ * on every render.
+ *
+ * The cache is process-lifetime; a page navigation away and back
+ * still sees the cached value. Callers that need to refresh (e.g.
+ * after `setUserQuota`) should call `invalidateAdminUserCache`.
+ */
+const adminUserCache = new Map<string, Promise<User | null>>();
+
+export function getUserAdmin(id: string): Promise<User | null> {
+	const hit = adminUserCache.get(id);
+	if (hit) return hit;
+	const pending = (async (): Promise<User | null> => {
+		try {
+			return await apiJson<User>(`/api/admin/users/${encodeURIComponent(id)}`, {
+				credentials: 'same-origin'
+			});
+		} catch {
+			return null;
+		}
+	})();
+	adminUserCache.set(id, pending);
+	return pending;
+}
+
+/** Drop cached admin lookups so mutations (quota change, role change,
+ *  delete) don't return stale data. Called with no arg = clear all,
+ *  or with a specific user id to drop just that entry. */
+export function invalidateAdminUserCache(userId?: string): void {
+	if (userId) adminUserCache.delete(userId);
+	else adminUserCache.clear();
+}
+
 export interface CreateUserInput {
 	username: string;
 	password: string;
diff --git a/frontend/src/routes/admin/+page.svelte b/frontend/src/routes/admin/+page.svelte
index 23b91c24..b10e5886 100644
--- a/frontend/src/routes/admin/+page.svelte
+++ b/frontend/src/routes/admin/+page.svelte
@@ -17,6 +17,7 @@
 		installPlugin,
 		listPlugins,
 		listUsers,
+		getUserAdmin,
 		migrationAction,
 		reextractAudioMetadata,
 		reextractPhotoMetadata,
@@ -883,6 +884,17 @@
 	// "still loading" — the stack treats undefined as no-owners-yet.
 	let driveMembers = $state<Record<string, DriveMember[]>>({});
 
+	// Owner user record for each PERSONAL drive, keyed by drive id.
+	// Personal drives have exactly one user-subject owner and their
+	// `d.quota_bytes` is null — the effective quota comes from the
+	// owner user's `storage_quota_bytes` envelope (see memory
+	// `project_user_envelope_quota_model`). We resolve the owner
+	// once at load time via the admin-scoped `/api/admin/users/{id}`
+	// endpoint so the Name column can show the username instead of
+	// the drive UUID, and the Quota column can display the envelope
+	// cap. Shared drives are absent from this map.
+	let personalDriveOwners = $state<Record<string, User>>({});
+
 	async function loadDrivesTab() {
 		drivesError = null;
 		try {
@@ -911,6 +923,26 @@
 			})
 		);
 		driveMembers = nextMembers;
+
+		// Resolve owner users for personal drives — used by the Name
+		// column (username instead of UUID) and the Quota column
+		// (envelope cap instead of "∞" for a NULL drive.quota_bytes).
+		// getUserAdmin caches per-id at module scope, so N personal
+		// drives owned by the same user share one fetch. Runs after
+		// `driveMembers` is populated because the owner subject id
+		// comes from the first user-typed member of the drive.
+		const nextOwners: Record<string, User> = {};
+		await Promise.all(
+			drivesList
+				.filter((d) => d.kind === 'personal')
+				.map(async (d) => {
+					const ownerMember = nextMembers[d.id]?.find((m) => m.subject.type === 'user');
+					if (!ownerMember) return;
+					const user = await getUserAdmin(ownerMember.subject.id);
+					if (user) nextOwners[d.id] = user;
+				})
+		);
+		personalDriveOwners = nextOwners;
 	}
 
 	function driveKindLabel(d: Drive): string {
@@ -2252,15 +2284,40 @@
 				</thead>
 				<tbody>
 					{#each drivesList as d (d.id)}
+						{@const owner = d.kind === 'personal' ? personalDriveOwners[d.id] : undefined}
+						<!--
+						  Effective quota:
+						  - Shared drive: `d.quota_bytes` (null → unlimited, shown as ∞).
+						  - Personal drive: the owner user's `storage_quota_bytes`
+						    envelope caps the sum of used_bytes across their personal
+						    drives (per memory `project_user_envelope_quota_model`).
+						    `d.quota_bytes` is always null for personal drives so we
+						    fall back to the owner's cap; 0 also means "no limit"
+						    (backend convention — see `User.storage_quota_bytes` doc).
+						-->
+						{@const effectiveQuota =
+							d.kind === 'personal'
+								? owner && owner.storage_quota_bytes > 0
+									? owner.storage_quota_bytes
+									: null
+								: d.quota_bytes && d.quota_bytes > 0
+									? d.quota_bytes
+									: null}
 						{@const pct =
-							d.quota_bytes && d.quota_bytes > 0
-								? Math.min(100, (d.used_bytes / d.quota_bytes) * 100)
+							effectiveQuota !== null
+								? Math.min(100, (d.used_bytes / effectiveQuota) * 100)
 								: null}
 						<tr>
 							<td>
 								<div class="user-cell">
 									<strong>{d.name}</strong>
-									<span class="muted"><code>{d.id}</code></span>
+									{#if d.kind === 'personal'}
+										{#if owner}
+											<span class="muted">{owner.username ?? owner.email}</span>
+										{:else}
+											<span class="muted">{t('common.loading', 'Loading…')}</span>
+										{/if}
+									{/if}
 								</div>
 							</td>
 							<td>
@@ -2288,8 +2345,8 @@
 										</div>
 									{/if}
 									<span class="muted">
-										{formatBytes(d.used_bytes)} / {d.quota_bytes && d.quota_bytes > 0
-											? formatBytes(d.quota_bytes)
+										{formatBytes(d.used_bytes)} / {effectiveQuota !== null
+											? formatBytes(effectiveQuota)
 											: '∞'}
 									</span>
 								</div>