# os.ErrClosed

- **ID:** `go/os-errclosed`
- **Domain:** go
- **Category:** io_error
- **Verification:** official
- **Fix Rate:** 80%

## Root Cause

File handle is already closed. Read/Write called after Close().

## Version Compatibility

| Version | Status | Introduced | Deprecated |
|---------|--------|------------|------------|
| 1.x | active | — | — |