Issue: Install process ends on domain.tld/?step=1

Were you in automatic or manual mode? Manual you have to click "Next" a lot, automatic you don't.

I just tried it with the latest build and was also forwarded to domain.com/?step=1
Apparently I was in manual mode. How do I set it to automatic?

If you are not in manual mode by choice, then Javascript is broken on your site. Please check your browser's Javascript Console for clues.

Did you correct your site's board URL as I suggested in your other report? A trailing slash will cause lots of problems.

I removed the trailing slash.
Im not sure what could be broken. xenforo upgrader works fine.
I was using firefox. In Chrome the upgrader did work, but also a manual process.

The yui-combo URLs (the Javascript combinator used by VaultWiki) return a XenForo security error rather than the proper Javascript code. It's likely you do not have the rewrite rules setup for /yui-combo/.

That only makes the upgrader be manual mode, though. The installer wouldn't use /yui-combo, so there is likely a different issue there. Do you have a test forum setup that is safe to uninstall/reinstall on, so I can see what's happening?

Now it also does the same in Chrome. Not sure how or why, because I never use chrome. All settings are default. No addons.
I am trying to install VW4G4build4

I cannot duplicate this on any of my test forums, and I cannot see in the source code why it would only do this near the end (if the form target URL was wrong, it should be wrong for every step). It may be related to server configuration or another forum setting. Again, if you have a test forum setup that's okay for me to run test install/uninstall a few times, please let me know in a PM.

It seems this was a result of using the old install folder somehow underneath the new version, like your other report. I don't think this occurred on the last reinstall.

It seems to me that VW would benefit from a file health check to check if all files are part of the latest version and no old files can be interfering.

While this is true, with both vBulletin's and XenForo's systems, file health check only works AFTER the add-on is installed. So it would be unable to detect that the install files are old if you haven't installed it yet.

Also, keep in mind that any manual patches to files will result in false positives during a file health check.

And finally, Gamma 4 already has built-in support for file health check.