Update: For NT 4 -> Vista it’s probably because I upgraded from NT 4 directly to XP with Unofficial SP4 slipstreamed, that probably what makes Vista stuck in a bootloop.

For some reason you can’t upgrade from anything below XP (except 9x) to Windows 8, the setup log complains about SAM and PolAcDmS. By upgrading through few Windows 8.0 build (I think it was 7850 and 7955) and 8.1 I have managed to get to Windows 10 1507 (x64)*, 11 bootloops.

For XP I didn’t know about it since I never touched anything below 3.51. I may have got the similar issue for VIsta as I remembered upgrading NT 4 -> XP and while upgrading to Vista it got stuck in a bootloop, I tried upgrading NT 4.0 to 7 another time and it worked??? Probably because I used RTM and not SP2.

*There’s an exploit with Windows 8.0 setup that allows you to upgrade from x86 to x64 by replacing install.wim and using some tools to make the setup keep everything.

my memory also thinks it may have been a permission in the registry?

So I tried looking through the NT 3.1 and NT 3.5 registries and nothing really stuck out that seemed like it would cause an issue upgrading NT 3.1 to XP. I tried modifying some values in the NT 3.1 registry but none of those edits made NT 3.1 go to XP, it still produces those same problems. I’m wondering if it’s a deeper underlying issue with the registry, or if there was just a key/value hidden deep in NT 3.1’s registry that I missed.

The one thing I did notice was that an NT 3.5 registry hive *does* load into NT 4.0’s REGEDT32 utility but an NT 3.1 registry hive (as well as a registry hive from an install of NT 3.1 that has been upgraded to NT 3.5) *doesn’t* load into NT 4.0’s REGEDT32, producing an error instead. Unfortunately, that makes diffing the NT 3.1 and NT 3.5/3.51 registry a much more tedious process than I was initially expecting since I was going to load a hive from NT 3.1 and a hive from NT 3.5 into NT 4.0 then use a piece of software that compares two loaded hives. But now that a NT 3.1 hive refuses to load into NT 4.0, that option is gone.

I solved a different registry issue with this NT Upgrade Path where, if you start at NT 3.5 instead of NT 3.1, XP would work fine but Vista would fail to complete the upgrade from XP (the install log complains about the SAM registry hive for some reason) and one solution I found to work was deleting the SAM hive in Windows 2000 (the last OS which doesn’t care if the SAM hive is deleted since it’s recreated at logon. The only caveat is that all user data and user accounts are deleted so you only have the barebones Administrator account remaining). I managed to get up to Windows 8 this way from NT 3.5.

But THIS registry issue with NT 3.1 to XP has me stumped. Would you happen to know what specific registry keys/values (or any other registry issues) in NT 3.1 have been causing the issues with XP? I’d completely understand if you don’t have the answer and aren’t willing to look into it anymore since it has been over 10 years now since you did this project and you have a lot more recent projects going on now, I was just curious since I really wanted to figure out a solution to this issue in the NT Upgrade Path project and play around with the results (plus I really wanted to learn about the ins and outs and why/how such an issue exists) and you’re one of the few people who documented the “NT Upgrade Path” in such detail.

Thanks!

Oh, okay! Thank you, I’ll have to compare a fresh NT 3.1 registry with a fresh NT 3.5 registry when I get a chance.

If it really is a registry problem, I wonder if it’s something to do with the permissions to modify/access the registry, or if it’s a value within a registry key.

I vaguely recall it being something in the registry, but I forget what.

The only way to find it would be diffing the registry from 3.5 to 3.51 and it should be hiding in there somewhere.

It kind of figures, NT 3.5 was really first ‘feature complete’ version of NT, 3.1 was really more of a get it the out the door already kind of release with that wonky Spider TCP/IP.

Sure enough, NT 3.1 was the problem. Started with NT 3.51 and now up to Windows 7. After 2000, upgrades wipe out custom themes and wallpaper for the most part.

I think it’s the upgrade from 3.1 to 3.5 that breaks the whole thing. I’m somewhat sure that ignoring 3.1 will give far better results. I think 3.1 sets security on some part of the registry that later versions need.