Too Many LUIDs Requested (0x535) – Quick Fixes

The Short Story

You're running some app or script, and boom – error 0x00000535. Windows says: "Too many local user identifiers were requested at one time." This is a resource limit on how many security tokens (LUIDs) your machine can hand out per boot. It's not a hardware problem. It's a Windows session thing. I see this most often with automation tools that spawn hundreds of threads, or with old .NET apps that leak handles. Don't panic – the fix is usually simple.

Fix 1: Reboot – Takes 30 Seconds

First thing: restart your computer. This clears all LUIDs from memory and resets the counter. If the error goes away after reboot, you're done. If it comes back after a few minutes, you need one of the fixes below.

Why it works: LUIDs are generated fresh on each boot. Rebooting wipes the slate clean.

Fix 2: Limit LUID Requests via Registry – Takes 5 Minutes

If rebooting doesn't stick, the real fix is to tell Windows to allow more LUIDs. But be careful – raising this limit too high can slow the system. I tweak it only when needed.

1. Press Win + R, type regedit, hit Enter.
2. Go to:

   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa

3. Right-click in the right pane, choose New > DWORD (32-bit) Value.
4. Name it LuidsMaxCount.
5. Double-click it, set Base to Decimal, and type a number between 1000 and 5000. I use 2000.
6. Click OK, close Regedit, reboot.

This increases the max number of LUIDs Windows can allocate. Had a client last month whose print queue script threw this error – upping to 2000 fixed it permanently.

Fix 3: Find and Kill the Leaky App – Takes 15+ Minutes

If the registry fix doesn't work, something is leaking LUIDs like crazy. This is the detective work.

1. Open Task Manager (Ctrl + Shift + Esc).
2. Go to the Details tab.
3. Sort by Handles (click that column header). Look for any process with >100,000 handles. That's your suspect.
4. If you see something like svchost.exe or a custom app with huge handle count, right-click it and End task. The error should vanish.
5. If you can't identify the app, use Process Explorer (free from Microsoft). Download it, run as admin, and look for the process with the most tokens. That's your leak.

Real-world story: I had a client who ran a database sync script every hour. It spawned a new thread per record but never closed them. After 200 records, error 0x535 popped. The fix was to rewrite the script to reuse LUIDs – but short-term, I just killed the rogue process each time.

What NOT to Do

Don't mess with SeIncreaseQuotaPrivilege or user right assignments – that's overkill and won't fix this specific error. Also skip reinstalling Windows unless you've tried everything. And don't set LuidsMaxCount above 10000 – you'll run out of memory and crash the system.

Quick Reference Table

That's it. Start with reboot, move to registry, then hunt the leak. You'll beat this error without disassembling your PC.