Yes, it's sad that the forums have been shut down. If you join the Sven Co-op discord, in the pinned messages of the #general channel there is a list of the most useful Github repositories which are now having to be used in lieu of the now-dead forums, for developing and sharing scripts and plugins.

Yes, it's a false-positive by Windows Defender. The sven co-op executable is safe, the detection has been reported and microsoft have acknowledged that it was a spurious detection and have updated the definitions accordingly. You can manually add an exception for it in the defender anti-virus section, you can force the latest virus signature database to be used or you can just wait until defender gets the next definitions automatically, at which point the issue will be resolved.
If you are a member of the Sven Co-op Discord, the appropriate post is here:
https://discord.com/channels/170051548284583937/272683006467112961/804865128545517568

PvP is possible by means of changing player classification, but it's limited and performs poorly. If you want to play deathmatch, SC isn't your game.

"I've put the mod folder into Steam/Steamapps/Common/Sven Co-op, svencoop addon and maps folder" - if that's what you did, then that's your problem. It's not a mod, you need to obey the existing file structure, e.g. maps in maps folder, sprites in sprites folder (of svencoop_addon or svencoop_download).
If you select the sub-folders and drop them into svencoop_addons/downloads they should merge with the existing folders and the assets should be in the right place.
If you can't find the maps from "Start New Game" then you put them in the wrong place, or left them in an extra folder.

Buy them from the Steam store, install them then run the "Install_bshift_Support.bat" and "Install_OpFor_Support.bat" installers from inside your ../common/Sven-Coop/svencoop" folder.

Alternatively you can join a game server which is running the maps at that time. This isn't as good a solution as buying and installing the expansion packs yourself, then you can play them as proper stand-alone HL expansions, as well as being able to play them co-op in Sven Coop.

There's no use for bhop in SC since it's a coop game. Instead of trying to race the map with bhop and spoil it for everyone else, try supporting your team mates, it makes for a more satisfying game in the end.

Gmod has many co-op hl2 maps, players vs bots..

Originally posted by Comrad1984:

Originally posted by Sparks:

yeah, except OC is dead.. RIP :'(

But why???

Because not enough people wanted it, the Devs left/moved on. RIP co-op games..

yeah, except OC is dead.. RIP :'(

Of course it's possible - if the maps are on your server, it will serve them to any joining player who doesn't have them, unless you have set it up otherwise.

It's just not legal, since you are then distributing paid-for content for free. However there are more than a few public servers with the BS and OppFor campaigns on them, and I don't know of any prosecutions to date - that being said, it's still preferable if you both legally own the mods in the first place.

Dynamite is correct, ignore bad noob advice - you will waste much time otherwise.

Even if they are not in you Start menu anymore, the HLSP support installers each have an obvious .bat filename in the SvenCoop directory, e.g. "Install_HLSP_Support.bat" etc.

So long as you own Half-Life on steam, and have run it at least once, the support installers will copy and modify your HLSP maps to make them work properly with mutliple players in Sven Coop. Same goes for Blue Shift and Opposing Force.

Because it would be mayhem..

In that case, check that you have forwarded the correct ports and actually check that they are working. Portforward.com has a free utility (trial mode) which tests ports for TCP and UDP which is very useful. Chances are there's a problem with your router which is still blocking incoming connections from the players trying to join your server.

Are you trying to join a server, or host one yourself? You only need to forward ports if you are hosting a listen (or dedicated) server. Sounds as if something is blocking your game's connection. Check your firewall carefully, for starters..