Frequently Asked Questions (FAQ)

Last modified: Winter 2021/22


NOTE: If the problem remains ask for help either on the forum or via IRC #0ad/ #0ad-dev(1), the game is maintained by volunteers who do all sorts of tasks, be patient.


Crash when starting the game

Do you have any antivirus software running? Try disabling it or add an exception for 0AD.
For Windows users, see also the Platform-Specific section below.

Crash when starting a match

Try to disable Post-processing in the game options, while leaving Prefer GLSL on.

No replay files are generated

Do you have any antivirus software running? Try disabling it temporarily or add an exception for 0AD.

Errors are displayed/
Game crashes on startup/
Permanently black screen

(1) Try to disable all mods not compatible with the new version via the Mod Selection page.
(2) If you cannot access the Mod Selection page, you should locate your user.cfg file (see wiki/GameDataPaths) and either delete it or search for mod.enabledmods. Replace this line with mod.enabledmods = "mod public".

(3) In some cases after disabling old mods, you might also have to delete the contents of your /0ad/mods/user folder. The wiki article wiki/GameDataPaths should tell you where to find it.

Why does the screen keep going black for a short time?

Try disabling FreeSync on the monitor to fix the black screen issue.

How do I increase or decrease the user interface?

Add gui.scale = "1.2" to your user.cfg file (see wiki/GameDataPaths), you can increase or decrease this number if you like, this will become an option with the release of A26.

How can I change the maximum/minimum camera zoom?

(1) Add view.zoom.max = "300" view.zoom.min = "30" to your user.cfg file (see wiki/GameDataPaths). Increasing view.zoom.max will let you zoom out further, decreasing the value for view.zoom.min will let you zoom in closer. The game's default values are 200 and 50.

(2) In single player mode, you can open the developer overlay with Alt + D and toggle the Restrict camera option so that you can adjust the camera zoom to your preferences.

Where do I find my replays, save files, screenshots and configuration files (e.g user.cfg)?

See wiki/GameDataPaths

Game is lagging

Network latency:
The lobby is hosted by us, but all the games you play connect you directly to the game's host. Depending on your location and internet quality, you may experience a high Ping/ latency with certain players. You can check your RTT (also known as Ping) with different hosts by pressing F11 or Alt+F11 and toggle through until you see the Network statistics panel.

NOTE: If you suffer from a consistently high Ping time, you will cause lag for all other players. Using an Ethernet cable can help a little.

Computation lag:
Yes, this is a common problem with the game. It will lag on most machines it is actually CPU bound, not your GPU. Try playing on smaller maps and limit the population to 600-800 units on the entire map.
Rendering, simulation (e.g. gathering / attacking) and pathfinder all contribute to the lag. If you have more units, more things need to be drawn which affects rendering, more things to calculate for unit activity affects simulation, and larger map sizes cause longer paths which affects the pathfinder.

NOTE: Multiplayer games are calculated on all computers simultaneously, with the slowest PC determining the game speed. If your computer is a bit outdated, you should reduce the graphics settings to a minimum. This might make the game faster for everyone.

Wiki/GamePerformance summarizes the problems, that need to be solved, to improve performance.

Frame rate - CPU and GPU workload

(1) Every frame that is calculated by the GPU is "prepared" by the CPU, one of them will limit your frame rate (FPS). When you select graphics effects, you create additional workloads for your GPU and CPU, causing your framerate to drop. Current PCs are mostly CPU limited in 0 A.D. because the game is not yet multi-threaded. That means they usually only use 1 core. Since graphics effects mostly affect the GPU, you can (on newer PCs) choose the higher graphics effects without sacrificing performance.
(2) Heating up the hardware leads to thermal throttling of the hardware. This effect is especially known for mobile PCs. If the hardware gets too hot, it throttles its performance until the hardware cools down again. Therefore, a limited but constant frame rate is usually better than a frame rate that fluctuates due to thermal throttling.
(3) VSync will also limit the framerate to the framerate of the monitor (I estimate 60 frames/Herz).

When hosting a game, the PC/laptop can barely cope with the required technical prerequisites, leading to game lag.

A way to ease the load on the PC/laptop is:
(1) Host a game, but let the host PC/laptop be a spectator.
(2) When the match starts, turn all graphics settings on the PC/laptop to a minimum, then choose one of the player's perspective. The idea is that normal observer/overload perspective allows you to see every detail on the map, which increases load. If you switch to a player's perspective, the PC/laptop only needs rendering what that player can see. This would only require the PC/laptop to render a small portion of the map, hence the load is smaller. Even better: Add an unassigned player and switch to that perspective. The unassigned player will never explore or expand, so its field of view would be limited to just the starting civic centre.

Balance graphics effects/ performance

To achieve an optimal balance between nice graphics effects and enough performance for a smooth game, consider this in 0 A.D.'s graphics settings:
(1) Enable GLSL
(2) Enable FXAA (no impact) and MSAA (little impact on performance, except for very weak GPUs)
(3) Enable water transparency
(4) Disable other water effects (reflection, refractions)
(5) Disable shadows


↓ Linux ↓

Game does not capture the left ctrl key press.

The left ctrl problem seems to be a result of the show cursor functionality of gnome-tweak.

Game fails to launch on Ubuntu.

If snap doesn't work, you can try the PPA (Ubuntu's Personal Packaged Application), see link below.

Triple screen, 0AD doesn't span over all screens!

Workaround it with windowed mode and xfce4 fullscreen.

↓ macOS ↓

0 A.D. cannot be opened because the developer cannot be verified.

The reason for this message is that 0 A.D. would need to be signed with a developer AppleID, which costs an annual subscription. At the moment, this problem can be bypassed for the installation by right-clicking and clicking Open.

All but player silhouettes and menues are just white.

Disable the graphics option Antialiasing.

↓ Windows ↓

Game crashes on startup.

error while dumping stack: No stack frames found
errno = 13 (Insufficient access rights to open file)
OS error = 0 (no error code was set)

Perhaps the wrong GPU is simply being used. For a detailed explanation of how to set it up correctly, see the following wiki article: wiki/SwitchingToYourPCsDedicatedGPU.

Game does not render correctly/
Rainbow colors

You need to adjust the property settings of the 0 A.D. application, see the link below.

Mouse cursor disappearing

Go to the Graphics (general) settings tab and switch to Windowed mode. After restarting the game, the mouse cursor should be visible all the time.


My friend cannot join my game and I cannot join their game.

Try disabling it or add an exception for 0AD.

If you forward the port, everyone will be able to join you. If you use STUN when hosting, probably many but not everyone will be able to join you. If you can't join someone else's game, there's nothing you can do about it other than informing the host that he should port forward or host your own game.

Failed to connect to the server. UDP port 20595 not being forwarded.

This error message is almost always caused by an incorrect network configuration on the host side, not by a bug in the game. Please ensure that the host has the UDP port 20595 forwarded at their router to their private IP address.

How to do port forwarding?

Port forwarding is a way to make a computer on your network accessible to computers on the Internet, even though they are behind a firewall/router. This is commonly used when playing games or downloading files. If you have forwarded a port in your router settings, it is referred to as an open port. 0 A.D. uses UDP 20595 by default.
Wiki/Manual_SettingUpAGame#Settingupyournetwork lists links to some router manuals.

Registering for the Game Lobby does not work:

- "Certificate expired"
- "The stream has been closed by the server"
- "An I/O error occurred

Try to disable TLS via Settings => Options => Lobby

NOTE: There is a limit to the number of accounts you can submit per hour; if it doesn't work, try again later.

"Authentication Failed"

This message usually appears, when you have got a typo in your password or username. If you are sure both are correct, you could create a forum account and contact user1.

I forgot my Game Lobby password.

Resetting is currently not possible via the user interface, you would need to create an account on the forum and contact user1.

The Game Lobby is empty.

You are probably using an older version of the game, see for the latest version.

How to play online?

Go to Multiplayer --> Game Lobby --> Create a new account, then you should see this page, now you can join a game or set one up yourself via Host Game.

How to play via LAN?

See this forum thread with detailed instructions - Multiplayer on LAN (16/Jan/17).

Can I host my own lobby/ server?

Yes, detailed instructions can be found in this Github repository: So far, there is no way to run a game on a central server. One of the players is always the host.

NOTE: Don't forget to modify your user.cfg file to connect to the correct lobby.

How can I ban observers in multiplayer mode?


  • You can set up a password when you host a game.
  • In the settings under General, find Observer limit, set it to zero and no one can join after the game starts.
  • Open the chat window and type /kick (person can rejoin) or /ban (person can't rejoin) followed by the user nickname. Only the host can kick out observers.


How to beat the AI and get better in this game?

Read these forum threads and you will defeat the AI and most likely become a competitive player in the Game Lobby:

Alternatively, you can watch Youtube replays (see Miscellaneous below) of pro players or download their replays to better see their build order and which tech upgrades they focus on.
You can find some replays for A25 here: Game Replays - Alpha 25

What is the difference between Random, Skirmish and Scenarios?

Random: All settings can be adjusted and the map looks slightly different every time.
Skirmish: The number of players and map size is fixed, everything else can be adjusted.
Scenarios: Settings cannot be adjusted, everything is fixed.

What does the triangular icon above my unit indicate?

It shows the current rank of your unit. The bar increases during combat, when it is filled, its rank increases automatically and your unit becomes a better fighter, but its ability to gather resources decreases. The Rank icon and Experience status bar can be toggled on/off in the Settings on the Game Session tab.

How to interpret these resistance numbers in the tooltip?

There are three types of damage: Hack, Pierce and Crush.
(1) Hack damage is usually inflicted in close combat by infantry or cavalry units.
(2) Pierce damage is dealt by ranged units, either infantry archers or skirmishers or even special siege units such as bolt shooters.
(3) Crush damage is caused by siege units such as catapults or rams.

The combat system works by matching the attack type with the resistance type. In the image below, the Gallic Mercenary Cavalry has a 6.5 Hack attack and the Athenian Hoplite has a 5 Hack resitance level. The value in brackets is the effective resitance percentage and calculated like this: 1-0.9resitance level (1-0.95 = 41%). For each attack made by the Gallic Mercenary Cavalry, 59% of their hack attack will deal damage to the Athenian Hoplite.
Attack damage and resistance levels can be increased through technology upgrades, unit ranks and auras.

Is training units in batches more efficient than training one at a time?

As a rule of thumb, training units with batches is more efficient the longer you do it and the larger the batch is.

Can I order my units to run?

No, the unit only runs when it flees or when it is called into formation. There is no specific function that you can use to command a unit to run.

How do you destroy a building instead of capturing it?

Click with the right mouse button while holding down the ctrl key on the building you want to destroy.

How does capturing work?

The buildings have capture points for all players. If a player reaches 100% of the capture points for that building that player gains control over that building. Capture points can be gained by ordering units to capture that building or by that building standing inside a players area of influence (the player-coloured borders).

Where can I find all keyboard combinations for the game?

(1) Either in the game itself via the GUI Hotkeys button or
(2) see wiki/HotKeys.

How do I select idle units?

You can assign a specific Hotkey via the GUI for selecting:

  • Builders (unit that can construct buildings)
  • Workers (unit that can gather resources)
  • Warriors (unit suited for fighting)
  • Any idle unit

In addition, press the Include offscreen key, by default the Alt key, to select all.

How do you select only military units?

Press Alt and draw a rectangle over your units.

Can you make groups of units?

Select a bunch of units and then press Ctrl + 1, you can make more multiple groups by using different numbers. To select this group, press the 1 key or another number key to which you have assigned your group.

How does trade work?

Either you build two markets and have traders run from one to the other or you send your traders from your market to one of your allies, the latter being more lucrative. Docks can also be used as market destinations.
Via the menu Barter&Trade you can set what is traded by clicking on the up or down arrows for each resource.

Does the game have cheat codes?

Yes, they are all listed here: wiki/Manual_Cheats.

How can I get units to move as individuals and not in formation?

Click with the right mouse button on the symbol at the top left, the small indicator changes the symbol.

How do I get a Game Lobby rating and how is it calculated?

Currently, only 1v1 matches are rated, and this option can be turned on or off by the host of the game. When the option is turned on, it will be displayed at the bottom of the game settings page. You will start with a score of 1200, which will increase if you win and decrease if you lose. After your first rated game, the rating will be visible.

NOTE: The rating adjustment is calculated with a simplified ELO algorithm, the exact details can be found here:

How do I report a user who quits a rated game without resigning?

You need to find the correct replay file (see wiki/GameDataPaths) and upload it here: Ratings Disputes and Offence Reporting (11/Jun/21).

How are the points for total, economy, military and exploration calculated?

(1) Total = Sum of economy, military and exploration score
(2) Economy = Resources gathered + trade income, divided by 10
(3) Military = Sum of enemyUnitsKilledValue, unitsCapturedValue, enemyBuildingsDestroyedValue and buildingsCapturedValue, divided by 10
(4) Exploration = percentMapExplored, multiplied with 10


Main game

How can I contribute?

We can always use another helping hand for this project. There are several ways to help and contribute:

For more details, check the wiki/GettingStarted article. Contact us through the forum or via our IRC #0ad/ #0ad-dev(1) channels.

If I find a solution to a bug, what should I do?

We use Phabricator to manage patches. You can upload your solution there and request a review of your patch. If the developers accept it, it will be added to the development version and later ends up in the bundled release version. Details on how to submit patches can be found here: wiki/SubmittingPatches.

NOTE: The only thing that gets a patch committed is a team member who pauses work on their own feature to review something. So if you feel you are not being heard, you may need to nag a developer, the best way is usually via IRC #0ad/ #0ad-dev(1).

Where and how should I report bugs?

Guidance on how to report bugs correctly can be found here: wiki/ReportingErrors.
Before creating a ticket, you are encouraged to do a quick search, as the issue may already be known. You can use the search box below to search all tickets (open and closed) by title.

Map making

How to get started?

The game comes with a Scenario Editor (aka Atlas) for information see wiki/Atlas_Manual and Scenario Design/Map making in our forum.

Can you recommend a video?

This tutorial was made by a Youtuber called Tom0ad - How to easily turn ANY Country into a 0AD Map! - 0AD Map Making (28/Mar/21).


How to enable mods?

See wiki/Modding_Guide

How to get started?

The game itself is developed to be highly modifiable, to get started see wiki/Modding_Guide and wiki/Mod_Layout.
Taking a look at small existing mods (e.g ffm_visibility or Battle Mod) might help to better understand how things work.
Some total-conversion mods are: Hyrule Conquest, Delenda Est or 0AD City Builder.

What to do if I need help?

(1) You can ask via IRC #0ad/ #0ad-dev(1).
(2) You might find old threads in the Game Modification subforum answering your questions, otherwise you can create a topic and ask for help there.

Can I use the game assets?

Yes, you only have to comply with the 0AD license.
"0 A.D. is released as open source: you can freely use, copy, modify and distribute the game's source code and data files, as long as you include attribution to Wildfire Games and let anyone freely modify and distribute any of your own modifications to the game's files."

Where to find the source code?

Here you can find all the information on how to get the source code and build the game: wiki/BuildInstructions.

Is there a documentation for editing the XML files of entities?

This page lists the components that can be added to entities and the XML syntax for their initialisation data.

Can I add my mod to the in-game download area?

Yes, you would need to upload it to, just follow the instructions below.


When will the next version be released?

When it will be ready. Unfortunately we can't be much more specific than that, there are too many things we just don't know. We're working on the game in our spare time, so we don't know how much time we'll have to make the game.

Why is this game still in alpha?

A developer wrote (21/Mar/21): "0 A.D. is also still quite laggy, and needs a fair few improvements before I think it's ready for a more mainstream audience. I would push towards dropping the 'alpha' from the name, but that doesn't mean it's quite ready."

Will you put the game on Steam?

We're going to look at putting the game on Steam to make it easier for people to find out about it, but not until we get to the beta stage at the earliest. We want the game to be as good as possible so people don't miss it among all the other games that are there.

Is the website up to date?

Yes, but gameplay related infos (Features, Factions, Game Manual) are a bit outdated. This needs to be fixed, if you want to help us, raise your voice either via the forum or through IRC #0ad/ #0ad-dev(1).

How to keep up with the game?

For casual players there is no channel that summarizes progress. From time to time there are some social media posts and a development report, but they are rare.
For players with technical background, you can read the wiki/Changelogs, check committed patches on Phabricator or the timeline on Trac.

Does 0AD use any social media accounts?

You can find a list of all accounts at the bottom of our homepage

Are there Youtube channels about this game?

The four most popular channels are:

Does 0AD have a Discord?

There is no official Discord, but there are unofficial servers:

How about more factions?

There are mods that add more factions to the game (see
Likely candidates: Han Chinese (20/Apr/21) , Zapotecs (7/Apr/17) and Nomads Xiongnu(29/Apr/17)
The concerns, for adding new factions, mainly revolve around balancing all the factions so that they are equally strong, but still different from each other and to be historically accurate.

Will you add support for single-player campaigns?

It has been added to A25. For more information, see the links below.

NOTE: Mapmakers who are willing to work on a campaign, please contact us (via forum or IRC #0ad/ #0ad-dev(1)), we would appreciate your contribution to the implementation of the campaign or a tutorial.

Does the game have an in-game store, is it freemium or pay-to-win?

No, everything of the game is totally free and open source. We only use donations to pay for server hosting, etc.

Would it be possible to have access to old versions of 0AD?

Yes, on this page - - you can find all released versions and some statistics about how many times each version has been downloaded recently.

NOTE: Additional statistics from users who have enabled the Feedback setting in the 0ad app can be found here:

Can you recommend a presentation or video about 0ad?

Who are the team members?

You will find a list of names in the Wildfire Games Team Wiki and in the Staff Directory in our forum.

What to do if I have a question that is not part of this FAQ?

Join IRC #0ad/ #0ad-dev(1) or check the forum's help & feedback section where many questions have already been answered. You may also ask any new questions there.


(1) Most active team members are in the CET time zone. The chat is logged

Last modified 2 weeks ago Last modified on Jan 5, 2022, 2:25:51 PM

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