How can I stop Steam checking for updates for an offline machine?

I copied my Steam folder from my laptop to my PC in my attempts to try and get some of my games to work offline. I followed this answer in regards to editing the loginusers.vdf file but when I went to try and see if it worked Steam went to search for an updates, failing to connect to the internet and saying that Steam needed a network connection. correct me if I'm wrong but quite sure that's the opposite of being offline.

Before copying my Steam Folder I did boot up Steam just to make sure there were no updates pending for it so at the time of copying it it was up to date and I can't just connect my PC to the internet as it's too far away from the router for an Ethernet Cable (and there's ~6 years worth of Windows/Misc Program Updates since this PC has never been connected to the internet since I first got it).

So how can I stop Steam checking for updates for an offline machine?

There are a few small workarounds to get back your Offline mode after copying your Steam folder (if they didn't patch it out by now).

If you were online on Steam on your other machine you can change the offline computer's date-time to the time you were last online on the other one.

Also: If it worked, write down the time! Steam offline mode can expire and ask you to reconnect to the internet and changing the date again will "fix" this.

Another way to deal with it is described here This wants you to change the offline value from 1 to 0 in the steam/registry.vdf file.

The path of the registry setting is Registry / HKCU / Software / Valve / Steam / (Note, that this will turn off offline mode. You'll need to re-enable it and having a backup is very useful.)

And finally from this answer:

Create a steam.cfg file with the following content and put it in your Steam directory.

BootStrapperInhibitAll=enable
BootStrapperForceSelfUpdate = disable
ForceOfflineMode=enable