Windows legacy file naming and compatibility

Discussions regarding Windows file naming have focused on the tension between system optimization and legacy compatibility. Microsoft has warned users against disabling the 8.3 File Naming mechanism, a feature dating back to MS-DOS that creates short aliases for long filenames. While some users attempt to disable this feature to improve performance in file-heavy environments, Microsoft cautions that doing so can break older applications that rely on these short names.

Additionally, Windows 11 continues to enforce restrictions on specific reserved keywords inherited from the MS-DOS and CP/M eras. Users are prevented from using names such as ‘CON’, ‘PRN’, ‘AUX’, ‘NUL’, and various ‘COM’ or ‘LPT’ ranges, which were originally reserved for hardware devices. Microsoft developers indicate that maintaining these restrictions is necessary to prevent breaking existing programs and scripts. While some testing on Windows 11 26H2 suggests that certain reserved names with extensions might be creatable, they may still cause unexpected behavior in environments like PowerShell.