The only times I was off the release path:

early 98 - that Win98 RC from around Jan 1998
early 01 - the last Whistler before they dropped Luna on everyone
early 06 - XP 64 (the xp everyone hates)

I don't consider prototype Windows versions a precious fascination and reverted pretty fast beyond their testing period anyway (they were very broken). Longhorn means nothing to me.

The only one I have is Windows 7 build 7100, also known as Ultimate Edition Evaluation Version. It runs surprisingly fast on a Pentium 4, certainly better than how Windows became bogged down in later life.

It can't be registered though, so no SP1, no windows updates, no Edge, no IE11 (it uses IE8), and it's always reminding me that it's "counterfeit", even though it came from Microsoft. Non-microsoft products can be installed though, so it's not entirely stuck in the old days. Still, I'm not really sure why anyone would desire such a situation.

I'm still using Windows 8 Developer Preview (build 8102, x86, debombed & activated) as a daily driver on one of my old PC"s.
It is full of bugs and quirks, but that's the point 😀))
Solving and circumventing them is fun 😀))

Robbbert wrote on 2024-10-23, 05:04:

The only one I have is Windows 7 build 7100

Loved that one, reminds me of my traineeship in Canada. I had this version for a while on my Vaio FZ38M. It ran smooth as far as I recall. Worth noting is the default wallpaper.

if i remember right i think the N versions have media player removed not sure about K, last obscure version i tried out was Neptune, was a while ago i think it used a mix of drivers from 2000 and 98, also got a copy of Nashville tho i dont think it differs much from 95 havent tried it out yet. also got some early builds of vista and win 7 from when they first released they're pretty unusable as a lot of programs are incompatible.

N was Media Player removed, K removed Messenger.
I didn't think of beta's and the like!

Yes I remember running Windows 2000 rc2, Maybe I ran 1 as well? Apart from Win95 I think 2k was the only new OS I was actually excited about.

I had an OS/2 Warp 3 beta. During installation process I had to feed it with Windows 3.1 disks.