| odename | Preliminary name | Final name | Notes |
| colspan="4" style="background: #f9f9f9; text-align: left;" | Windows family |
| anus | |Windows 3.1 | |
| ato | |Windows for Workgroups 3.1 | |
| nowball | |Windows for Workgroups 3.11 | |
| hicago | |Windows 95 | |
| etroit | |Windows 95B (OSR 2) | |
| emphis | Windows 97 | Windows 98 | The codename was the key to activating an easter egg in Windows 98: - open the "Date and Time" control panel;
- go to the "Timezone" page;
- hold the Control key and drag a line with the mouse cursor from Memphis, Egypt (or maybe Cairo, codename of Windows NT 4 - the map is too small to tell) to Memphis, Tennessee. Still holding the Control key, drag another line from Memphis to Redmond, Washington;
- a window opens with the credits for Windows 98.
|
| eptune | |N/A |Never released. |
| illenium, Georgia | |Windows Me | |
| colspan="4" style="background: #f9f9f9; text-align: left;" | Windows NT family |
| S/2 3.0 | Windows NT | Windows NT 3.1 | There never was a Windows NT 1.0. The version number was chosen to mirror the Windows version number at the time |
| aytona | |Windows NT 3.5 | |
| airo | |Windows NT 4.0 | |
| olfpack | |Cluster Server | |
| ydra | Terminal Services | Terminal Server | Terminal Server adds "multiheading" support to Windows, and the hydra was a mythological monster with multiple heads. |
| mpala | |Windows NT 4.0 Embedded | |
|Windows NT 5.0 |Windows 2000 |A watershed in Windows naming: - first major Windows release since Windows 2.0 without a codename;
- first major Windows NT release whose workstation variant was named "Professional" instead of "Workstation";
- first major Windows NT release without the "NT" designation in the trade name, which caused confusion when Windows ME was released. The Windows line has been since dropped altogether, and Windows NT operating systems are now simply referred to as "Windows".
|
| stroid | |Windows 2000 Service Pack 1 | |
| anus | |Windows 2000 64-bit |Same codename as Windows 3.1. |
| dyssey | |N/A |Never released. |
| histler | |Windows XP |Merge of Neptune and Odyssey. Named after Whistler, British Columbia, where design retreats were held. |
| antis | |Windows XP Embedded | |
| reestyle | |Windows XP Media Center Edition 1.0 | |
| armony | |Windows XP Media Center Edition 1.5 | |
| histler Server | Windows .NET Server | Windows Server 2003 | One of many unrelated Microsoft projects of the time to carry a ".NET" designation. See: Microsoft .NET. |
| obcat | |Windows Server 2003 Small Business Edition | |
| a href="/encyclopedia/Windows-Longhorn" title="Windows Longhorn">Longhorn | |N/A |Not released yet (as of March 2005). Named after a bar in the Whistler-Blackcomb resort; initially planned as an "interim release" between "Whistler" and "Blackcomb". |
| a href="/encyclopedia/Windows-Blackcomb" title="Windows Blackcomb">Blackcomb | |N/A |Not released yet (as of March 2005). Named after the Whistler-Blackcomb resort ("Whistler" was also a codename, see above). |
| colspan="4" style="background: #f9f9f9; text-align: left;" | Others |
| |COM+ 2.5 |Microsoft .NET | |
| |COM+ 2.5 Runtime (COR) |Microsoft .NET Framework | |
| uartz | ActiveMovie | DirectShow | |
| arwin | Microsoft Installer | Windows Installer | |
| odot | |Microsoft Layer for Unicode |Named after the play Waiting for Godot (centered around the failure of a man named "Godot" to appear and the endless wait for him), because it was felt to be long overdue (source). |