I was struggling to understand why my other Tumbleweed box did not have an /etc/login.defs file (but it DOES have an /etc/login.defs.d directory, of which I find no mention in the man pages).

Now I see that both my work laptop (the one with the original problem) and my home PC (the other Tumbleweed box) have a /usr/etc/login.defs file.

To reply to Carlos, I do not know how or why I got those values in the /etc/login.defs on the work laptop. It should have been removed like on my home PC, I suppose. I also do NOT have an /etc/login.defs.d directory on the work laptop.

From: Andreas Mahel <andreas@mahel.net>
Sent: Friday, December 3, 2021 08:36
To: support@lists.opensuse.org <support@lists.opensuse.org>
Subject: Re: No more available UIDs?

Am Donnerstag, 2. Dezember 2021, 13:25:15 CET schrieb Guadagnino Cristiano:
> It worked.
> The new user has UID 1001, so it means the old config was limiting UID to
> have values <= 1000. I am really perplexed though, as I had never changed
> login.defs before. Later I'll see how it is defined in my other Tumbleweed
> box.

On my Tumbleweed box there actually exists no /etc/login.defs, as this had
been moved to /usr/etc/login.defs.
You could check if /usr/etc contains a valid login.defs and if it does and the
version in /etc does not contain any adaptions you need, you could just remove
the version from /etc

/Andreas

--
Time flies like an arrow.
Fruit flies like a banana.