Fix 0x00000223 ERROR_INVALID_QUOTA_LOWER on Windows

When this error hits

You're managing disk quotas on a Windows 10 or 11 machine — maybe a shared drive or a server volume — and you try to reduce a user's quota limit. Say they were allowed 10 GB but you need to cut them to 5 GB because the volume is running out of space. You run fsutil quota modify or go through the GUI under Properties > Quota and set the new lower limit. Windows kicks back with error 0x00000223 and the message: An attempt was made to lower a quota limit below the current usage. The user is already using 6 GB, and you tried to set 5 GB. Windows flat-out refuses.

What's actually happening here

The NTFS quota system tracks two values per user: the quota limit (the cap) and the current usage (how much data they've stored). The rule is simple: you cannot set a quota limit lower than the current usage. Windows enforces this because lowering the limit below usage would mean the user is instantly over their quota — and the system can't magically remove files to free up space. It's not a bug; it's a safety guard built into NTFS. The error code STATUS_INVALID_QUOTA_LOWER (0x00000223) is returned by the NtSetInformationFile syscall when the quota entry is modified but the new limit is less than the current usage.

The fix — step by step

Check the user's current usage. Open Command Prompt as admin and run:
```
fsutil quota query C:
```
Replace C: with your volume. Look for that user's line — you'll see Limit, Warning, and Usage. If usage is 6 GB, you cannot set limit below 6 GB.
Two options: reduce usage or delete quota entry.
- Option A — Free up space under that user's account. Delete or move files until usage drops below your target limit. Then apply the new limit.
- Option B — Delete the quota entry entirely, which resets usage to 0. Then create a new quota entry with your desired limit. Be careful: deleting the entry doesn't delete files — it just resets the tracked usage. The user's files remain.
To delete a quota entry via GUI:
Right-click volume > Properties > Quota tab > Quota Entries > select user > Delete. Then add a new entry with your limit.
To delete via command line:
```
fsutil quota delete C: <userSID>
```
You'll need the user's SID. Get it with wmic useraccount where name='username' get sid. After deletion, usage resets to 0, and you can set the limit fresh.
Set the new quota limit:
```
fsutil quota modify C: <limitInBytes> <warningInBytes> <userSID>
```
Example: fsutil quota modify C: 5000000000 4000000000 S-1-5-21-... sets a 5 GB limit with 4 GB warning.

If it still fails

Three things to check:

Quota enforcement is on. Go to Quota tab and verify Enable quota management is checked. If it's off, no changes will stick.
You're targeting the right volume. Quotas are per-volume. Make sure you're modifying the volume where the user's files live, not a different partition.
Permission issue. You must be admin. Even then, some scripts that pass the wrong SID format (like without domain prefix) silently fail. Use whoami /user to confirm the SID format.

If you still get 0x00000223, the user's usage hasn't dropped enough. Run fsutil quota query again and compare numbers. The error is blunt but honest — you cannot break the invariant. Work with the usage, not against it.

Bottom line: NTFS quotas exist to prevent disk abuse, but they also protect users from accidental data loss. The error 0x00000223 is Windows saying "I can't orphan your files." Move files first, then set the cap.