FAQ (Frequently Asked Questions)
Please check out this wiki page before asking for help in the #mod-help channel of our Discord server!
WHEN IN DOUBT!!! VERIFY PORTAL 2 GAME FILE INTEGRITY IN STEAM FOR BOTH THE HOST AND CLIENTS! MAKE SURE ONLY THE HOST IS RUNNING THE MOD!!!
FAQ Categories:
There are currently some issues with the launcher or Portal 2 that can't be fixed or problems that have been on and off. Below are some of the common issues and some solutions to them. We've had a lot of cases where some people's computers or Portal 2 installations won't cooperate and can't run the mod. We will try our best to help you in a mod-help post on our Discord server if any of the below solutions don't work.
Not too long ago (as of February 9th, 2024), Valve updated Portal 2 several times, patching exploits and other bugs. Unfortunately, the update done on February 5th, 2024, has thrown off the launchers patching for 2.1.0 and older, causing them to no longer work, crashing the game immediately as it starts. This crash hasn't been the case for 2.2.0 and newer releases, as a different patching method is used with a Source engine plugin at runtime rather than patching the DLLs and then starting the game, which the launcher initially did.
Because of updates done to Portal 2, as mentioned in the above issue, our byte patches for Linux have misaligned to a point where they won't work, crashing the game. We need help fixing this due to the tedious nature of reverse engineering, the need for more knowledge among developers to accomplish such a task, and those who know are currently unavailable. However, our Windows patches still work. The current solution is to use Proton or similar for Portal 2 to be treated as if it were run on Windows, meaning it uses the patched Windows DLLs. Proton or similar will also use the Windows version of the P2:MM Source engine plugin to run the mod, as we still don't have the Linux version compiled. We plan to get this fixed eventually.
As mentioned in the first issue, because of updates done to Portal 2 on Windows, there might occasionally be a "Runtime Error" pop-up when the game starts. Our patches cause this error, but thankfully, nothing appears to be broken. If this pop-up appears, don't close it. You can see an image of it below. The game will not close and will run like nothing has happened.
For those having problems with a "No Steam Logon" error that occurred not too long ago, Valve has made updates to Portal 2 that have caused these disconnect messages to appear for all multiplayer sessions and not just P2:MM. However, later on, Valve seems to have fixed this issue, but if it ever appears, make sure your game is up to date.
In older versions of the launcher for Windows systems, checks for Portal 2 installed on a different drive were not done correctly, causing the mod not to be mounted correctly. Sometimes, it can't find the path correctly and needs to be manually defined. This problem wasn't the case for Linux, as external drives are handled vastly differently than Windows. Even though it should be ensured that this issue is fixed, every so often, a Portal 2 installation on a different drive still causes problems.
The simplest solution for Windows would be to specify the path manually. The launcher will then be able to find your Portal 2 installation. If that doesn't work, moving your Portal 2 installation to your central C: drive is simple.
A tacky solution if you don't want to transfer your installation or can't due to lack of disk space is to manually make a portal2_dlc# folder (# being the next number after whatever other portal2_dlc# folders you have), sticking the inside contents of the ModFiles (p2mm\ModFiles\Portal 2\install_dlc\(these files)) from the local p2mm directory (C:\Users\(current user)\Documents\p2mm for Windows, ~/.config/p2mm for Linux, and ~/Documents/p2mm for Steam Deck/Steam OS 3.0) into the portal2_dlc folder. From there, you set the launch options to Portal 2 -novid -allowspectators -nosixense -conclearlog -usercon +clear +map mp_coop_lobby_3 (see image below), then manually start the game through Steam. This manual setup should work.
A minor issue can occur if you're setting up the AppImage version of the launcher to run it in Steam by adding it as a Non-Steam game, but it's also your first time launching it. For some reason, running through Steam blocks the launcher's ability to detect the system's language automatically. This bug doesn't break or crash the launcher as it is programmed to default to English if it can't get the system's locale or an unsupported one is detected. Our launcher has been translated to support Español, Français, Polski, Português (Brasil), 简体中文 (Simplified Chinese), and 繁體中文 (Traditional Chinese). Any other will default to English.
There is a solution, but it's only applicable if you still need to start the launcher for the first time. Just launch it via the executable and not through Steam. However, if you have already launched it via Steam, you must change the language in the settings.
A: No, only the host needs the mod installed for others to connect. If the clients install the mod, interference with the host and specific systems the mod uses can occur.
A: It's recommended for players to join using vanilla Portal 2, but other players can have mods like SAR (Source Auto Record) installed and be able to enter a server. Other mods on the host machine that aren't SAR might cause P2:MM to be unstable or interfere with its operations, so it is recommended that you disable them before running the mod. Asset modifications/overrides done using Portal 2's DLC folder method (portal2_dlc#) should not cause problems as the launcher is programmed to make sure P2:MM has priority over the other folders, overriding any assets in lower-tier DLC folders.
A: We do not have a proper executable certificate because we all are broke, so the .exe version of the launcher will be flagged as a virus. This flag is mainly due to the use of pyinstaller. Some idiot used it to make a virus, which is not what it's meant for, so most, if not all, anti-virus software flags any software using the pyinstaller compiler. Alternatives are being investigated that won't cause problems. You should make an exception if your computer still won't let you run the .exe. If you're skeptical of our work, you can always look at the source code for P2:MM in the GitHub Repository.
Please do not make a Issue post or some statement in our Discord server without any prior research saying that the mod is a virus because it got flagged. These claims are unhelpful and can be deceptive. Associating the mod with viruses goes against our goals with Portal 2: Multiplayer Mod and can hurt our reputation.
A: There are two reasons for this. It happens if you're using the AppImage and do not have FUSE installed or have not given the executable permission to run.
FUSE needs to be installed to run AppImages. For some reason, some distributions don't have it installed by default. Information for installing FUSE on your distribution can be found here AppImageKit's Wiki
As for giving permissions, depending on your Linux distribution, double-clicking the executable should show a prompt asking if you want to execute the file. If this doesn't happen, you must chmod the .AppImage file. In your Linux distribution's terminal, use chmod a+x p2mm-*-x86_64.AppImage (* being the launcher version) to permit you to execute the file. You should now be able to run the file.
A: The ModFiles are around 1 MB, so this shouldn't be too long of a download. The average internet connection should be able to download this, but there are cases for specific individuals where it is hard to download something of this size. If you are having trouble downloading the ModFiles via the launcher, there's an included zipped-up version of the ModFiles on the latest release page. Hopefully, this works as a replacement for the launcher downloading the files for you. Once you've downloaded the zip, take the ModFiles folder and replace the one in your local p2mm folder, which is C:\Users\(current user)\Documents\p2mm for Windows, ~/.config/p2mm for Linux, and ~/Documents/p2mm for Steam Deck/Steam OS 3.0. Before copying over the newly downloaded ModFiles folder, close the launcher, and if there already are ModFiles and .temp folders, delete them both. You can start the launcher again after copying over the files.
A: This usually occurs when it's the first time launching the launcher or if the Portal 2 directory has changed. The launcher should be able to retrieve the path for Portal 2 automatically. Windows occasionally has trouble with Portal 2 installed onto another drive. Please check out this issue for more information. If not, go into the launcher's settings, go to "General Settings", then "Portal 2 Path". You can manually set Portal 2's game path by copying and pasting it into the input prompt or manually typing it.
A: For clients to connect to the host, the host needs to open their router's port. You must give your clients your public IP with the server's port. We do not have an exact tutorial on how to do this since all routers have different processes for setting up port forwarding. A simple Google search of your router's model relating to port forwarding should help you with your answer.
Hamachi, Radmin VPN, and playit.gg are recommended virtual networking tools that can help simplify this process if you do not know how, don't have the will, or are uncomfortable opening your router port for people to connect.
Portal 2 uses ports 27015 and 27016 and the UDP protocol.
Q: I'm getting a partner disconnect message and a bunch of text on the top-left corner of my screen when I load into Portal 2!
A: This means the launcher didn't load the mod onto Portal 2 correctly. Quit the game and press Update. If it asks you if you want to update, press "Yes". If not, close the launcher and go to the local directory where the P2:MM launcher holds its files. C:\Users\(current user)\Documents\p2mm for Windows, ~/.config/p2mm for Linux, ~/Documents/p2mm for Steam Deck/Steam OS 3.0. Remove the ModFiles folder, then open the launcher again. Click "Update" or "Start Game", and the launcher will prompt you to install the ModFiles. Press "Yes", and the ModFiles will be downloaded. If it doesn't work, please make a mod-help post on our Discord server.
A: This means you misconfigured the port forwarding, or something else is blocking the connection to your play session. Ensure the port is correctly set in your router's port forwarding settings. If you use Hamachi, Radmin VPN, playit.gg, or anything else, ensure they are configured correctly.
Portal 2 uses ports 27015 and 27016, and the protocol is UDP.
A: A password can be set once the game has loaded. All you have to do is open the developer console and type in sv_password (your password). Your clients will then have to input the developer console command password (your play session's password) before using the connect command.
A: As of version 2.1.0, support for SAR has been added to run alongside the Portal 2 Multiplayer Mod. Any launcher that still needs to be updated to this version will result in the game crashing when it tries to launch.
A: This can occur when you start a multiplayer session through the main menu buttons of Portal 2. Creating a play session this way locks the max player count back to the default two players. The launcher should automatically start you in the cooperative lobby. If you are already in the menu, you can begin a session using the console using the command map +mp_coop_lobby_3. Doing it through the console will not re-lock the player count.
A: This is intentional. The mod needs to start with a multiplayer map for it to setup and patch correctly. See the questions below if you want to play single-player or workshop maps.
A: Single-player maps can be started in three ways. The first way is to use the launcher's Custom-Launch-Options setting. Simply put in +map (single-player map here). You can also instead use +ss_map instead of +map for splitscreen. The next two are involved in game. You can use the chat command !spchapter (chapter number here) if already in-game. If you are on the menu of Portal 2, you can use the console command map (single-player map here), if you are in-game already, changelevel (map name here). We currently only support he official 62 single-player campaign maps. Any supported workshop single-player maps will be in the #community-maps channel on our Discord server. Any other from mods, the workshop, or other sources will either not work or be broken.
A: Before attempting to have people connect to you, make sure you and your clients have that workshop map subscribed and downloaded. They will be disconnected from the server if they do not have the map. For a list of supported workshop maps, please check the #community-maps channel of our Discord server. These have been specifically made for the mod or have had special scripting created to work with the mod. Currently, the maps listed in #community-maps have been confirmed to work. Any other single-player or cooperative maps in the workshop may not work or break when played. Please let us know if you want to suggest adding a map with custom support.
A: At the moment, no, but there might be added support for other mods in the future. Some multiplayer mods might work, but they will most likely break because they have yet to be supported. Also, due to the nature of some mods on Steam or in modDB, they most likely contain custom assets that must be downloaded by the host and clients beforehand. These mods also strip most of Portal 2's other maps and assets to free up space. Feel free to try some out at your own risk.
A: To start a session with split-screen, you must begin in the P2:MM launcher. You can also do this from the Portal 2 main menu if you've already loaded the mod.
If you are in the launcher, go to the launcher's settings, "Portal 2 Config", then "Custom Launch Options", and change the default +map mp_coop_lobby_3 to +ss_map mp_coop_lobby_3. The ss part stands for split-screen. Start the mod, and you should be playing in split-screen mode.
If you are in the Portal 2 main menu, open the console, type ss_map mp_coop_lobby_3, and press enter. Start the mod, and you should be playing in split-screen mode.
It is recommended to start in the main cooperative lobby (mp_coop_lobby3), but you can create a session on another map that begins with mp_coop. You can not start split-screen on single-player maps. You need to begin in the lobby and switch from there to use split-screen in a single-player map.
Please note that everything might not work as intended. The split screen user's username playing as P-Body is named "split".
A: No, you can't get achievements in P2:MM because P2:MM performs specific actions that require sv_cheats. Cooperative campaign progress is another issue influenced by sv_cheats. Read below for more info on that.
A: P2:MM can cause some weirdness with your cooperative saves, as the cooperative initiative saves are an internal system of Portal 2 and can't be controlled without extensive patches. Because sv_cheats (as mentioned above) is used to perform specific actions, this also contributes to some save weirdness. It's also been determined that in cases where the game fails to connect to Steam servers to check for cooperative save data and load it, progress will start back at zero until the user reconnects to the Steam servers.
Some ways you can manipulate/fix your save progress would be to use the following console commands:
-
p2mm_cut_progress: Resets all the cooperative initiative's progress to zero. -
p2mm_label_coop_completed: Marks all cooperative initiative maps completed. -
p2mm_label_coop_incompleted: Marks all cooperative initiative maps incomplete. -
p2mm_course_#_completed: Mark a specific cooperative initiative branch/course complete. You need to supply the branch number.
A: We don't know precisely what the issue with that is. It might just be that the game struggles a bit when there are a lot of players. Changing the level or restarting a level usually fixes it. While this does not impact anything, it is funny to see Atlas or P-Body sliding around while T-Posing.
A: This is a current limitation with P2:MM, and why, in the #community-maps channel of our Discord server, we ask for all users to have the map pre-downloaded the workshop map and restart Portal 2 before switching to the workshop map.
