Every time I try to look at the Skyrim mods on Steam Workshop, it says I'm on a new computer and makes me repeat an e-mail authorisation code before logging me on.

Any way to fix this?

I've ensured that Steam cookies are not deleted by my garbage collector.

For security and integrity reasons, I have removed Steam from Windows start up, and always play offline.

Well, you can disable this in Steam by going to your Steam settings, then in the Account tab click the Manage Steam Guard Account Security button and then disable it.

This is not the solution and I highly suggest NOT doing this.

@OP Can you check if your IP is being changed? This is a likely cause.

You could try accessing the workshop from within Steam itself, rather than a regular browser. That should avoid the need to log in.

I assumed he was doing this....
There's a bug in Steam that makes you have to log on manually even in the Steam browser.
Usually restarting Steam fixes this but on some systems it seems this ALWAYS happens (not sure of the cause)

I do believe every time you login on an actual web browser you have to verify with Steam guard each time though...
Or at least most of the time.

DAMN! So I'm not alone with this. I thought I was.
I am so annoyed by how I had to login each time on the Workshop when using it on the Internet.

Using the Workshop through Steam browser is not acceptable, because it lags by a delay of like 1-2 seconds for each time you move page. Incredibly annoying. And you can't have tabs. So the Workshop through the Steam browser svck and only online is OK enough.

Would truly want a solution to this.

More than likely this is a cookie issue or it could be some Internet Security software or AV software is preventing Steam from remembering your machine.

Well, I've checked that every cookie with Steam in the name is being preserved after the session, so unless they have a cookie with a strange name, that's not the issue.

I'll check out some of the other options suggested.

Hmm... the Workshop in a browser huh? I just used Steam browser (and was not a fan).

I'd probably just use the Nexus if I were you. More content, better organized. Easier to find what you want, and sorting by endorsemants means finding really good mods is fairly easy.

I posted an answer to this but instead of refreshing the page, the 'post' button logged me out! LOL.

Anyways, I get this problem because I have Firefox set to 'never rember history' and it deletes all cookies on exit.

CCNA is right on the mark here as far as I can see.

I don't have that, but whenver I open up my browser again, I have to relog. I also forced my browser settings to allow cookies on steamworks site.

Curiously, today I can log on to the Steam Workshop website without the "new computer authentication" biz (and, yes, I did shutdown overnight).

I just had to log on again. Furthermore, now it seems to remember me.

Using CCleaner, I've verified that this doesn't depend on any cookie acquired in the last few days, so perhaps there was a temporary glitch at Steam's end.