diff --git a/server/routes/user/index.ts b/server/routes/user/index.ts
index 86ab0961..64766bfa 100644
--- a/server/routes/user/index.ts
+++ b/server/routes/user/index.ts
@@ -22,6 +22,7 @@ import { getSettings } from '@server/lib/settings';
 import logger from '@server/logger';
 import { isAuthenticated } from '@server/middleware/auth';
 import { getHostname } from '@server/utils/getHostname';
+import { normalizeJellyfinGuid } from '@server/utils/jellyfin';
 import { isOwnProfileOrAdmin } from '@server/utils/profileMiddleware';
 import { Router } from 'express';
 import gravatarUrl from 'gravatar-url';
@@ -679,10 +680,20 @@ router.post(
       jellyfinClient.setUserId(admin.jellyfinUserId ?? '');
       const jellyfinUsers = await jellyfinClient.getUsers();
 
-      for (const jellyfinUserId of body.jellyfinUserIds) {
-        const jellyfinUser = jellyfinUsers.users.find(
-          (user) => user.Id === jellyfinUserId
-        );
+      const jellyfinUsersById = new Map(
+        jellyfinUsers.users.map((user) => [
+          normalizeJellyfinGuid(user.Id),
+          user,
+        ])
+      );
+
+      for (const rawJellyfinUserId of body.jellyfinUserIds) {
+        const jellyfinUserId = normalizeJellyfinGuid(rawJellyfinUserId);
+        if (!jellyfinUserId) {
+          continue;
+        }
+
+        const jellyfinUser = jellyfinUsersById.get(jellyfinUserId);
 
         const user = await userRepository.findOne({
           select: ['id', 'jellyfinUserId'],
diff --git a/server/utils/jellyfin.ts b/server/utils/jellyfin.ts
new file mode 100644
index 00000000..68d3c3c9
--- /dev/null
+++ b/server/utils/jellyfin.ts
@@ -0,0 +1,15 @@
+export function normalizeJellyfinGuid(
+  value: string | null | undefined
+): string | null {
+  if (!value) {
+    return null;
+  }
+
+  const normalized = value.replace(/-/g, '').toLowerCase();
+
+  if (!/^[0-9a-f]{32}$/.test(normalized)) {
+    return null;
+  }
+
+  return normalized;
+}