Windows ME

Windows Millennium Edition (referred as Windows ME) was the last 16/32 bit hybrid version of Microsoft Windows. ME was released as version 4.9, but Twitter user Albacore (@thebookisclosed) suggests that the kernel version might have been 5.0 initially, citing files from builds 2332 and 2348, with a version number of 5.0 and build numbers pre-2332.

It was released to manufacturing on June 19, 2000 and to retail on September 14, 2000. It was criticized due to its instability, and was sold on the market for a total of 402 days before being superseded by Windows XP on October 25, 2001. Some components of Windows 2000, such as the TCP/IP stack, were ported to Windows ME.

Prior to the release of Windows ME, Microsoft had planned for Windows Neptune to bridge the gap between the 9x series and Windows NT. However, Microsoft changed its plans in early 1999 and decided to release another 16/32-bit hybrid operating system, postponing the release of Neptune. Later, the Neptune project was scrapped in favor of Windows XP (then codenamed Whistler). Notably, some of the features scheduled for Neptune, such as the Help and Support Activity Center, were included in Windows ME.

Although generally perceived to be a failure, Windows ME introduced several features which would later be deemed beneficial, including Automatic Updates, System Restore, Windows Image Acquisition, and Windows Movie Maker. It is also the first consumer oriented version of Windows to natively offer support for USB mass storage devices.

Developer Release

 * Millennium build 2332.2 - Developer Release 1
 * Millennium build 2348.0 - Developer Release 2
 * Millennium build 2350.3
 * Millennium build 2358.0 - Developer Release 3
 * Millennium build 2363 - Developer Release 4
 * Millennium build 2368
 * Millennium build 2374

Beta 1

 * Millennium build 2380.2 - official beta 1
 * Millennium build 2394
 * Millennium build 2399

Beta 2

 * Millennium build 2400
 * Millennium build 2402
 * Millennium build 2403
 * Millennium build 2404
 * Millennium build 2408
 * Millennium build 2410
 * Millennium build 2416
 * Millennium build 2419 - official beta 2
 * Millennium build 2429
 * Millennium build 2434
 * Millennium build 2443
 * Millennium build 2447
 * Windows ME build 2452 - official beta 2 Refresh
 * Windows ME build 2455
 * Windows ME build 2460
 * Windows ME build 2465
 * Windows ME build 2466
 * Windows ME build 2470
 * Windows ME build 2476
 * Windows ME build 2481
 * Windows ME build 2487

Beta 3

 * Windows ME build 2491
 * Windows ME build 2495
 * Windows ME build 2499 - Release Candidate for Beta 3
 * Windows ME build 2499.3 - Release Candidate 1 for Beta 3
 * Windows ME build 2499.7 - official beta 3
 * Windows ME build 2509
 * Windows ME build 2513
 * Windows ME build 2516

Release Candidate

 * Windows ME build 2525 - Release Candidate 0
 * Windows ME build 2525.6 - Release Candidate 1
 * Windows ME build 2535 - Release Candidate 2

Release to Manufatcuring

 * Windows ME build 3000

Gallery
Screenshots of unidentified, unlabeled builds from Paul Thurrott.

BetaArchive forums

 * Windows ME Activity Centers
 * About ME, Neptune Betas