Failing to upload large (430mb) mod

Good day all. I have been attempting to upload my mod for the past week now.
I have a large mod that I aim to upload , I have split the mod in two parts , to allow each part to be within the 500mb max upload size. But even though the part 1 is 430mb, it produces an error when I attempt to upload. :"Failed to publish mod. Error unknown.

I get the error when using the website on Chrome as well as Firefox.
Further more, the eeror occurs when I attempt to use the ingame publishing option as well.

The mod is in .zip format as is required.
If anyone has any advice on how to upload an enormous two part mod successfully , please let me know.

Have a good day.

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@DodoNotDoDo Can you help? Also mod size limit should be removed to make life easier for people.

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Sorry for the issues. It looks like the problem is you’re logged on using your Steam account. While the site now supports Steam login so you can install mods, it doesn’t currently support publishing them. We’ll have to note that somewhere. If you log on with your Xbox Live account and have the file below the 500mb limit, you should be ok. If you continue to have issues, let me know the approximate day/time of your attempt and that will make it easier to review error logs.


yea I think modding in general is lacking details when an issue arise. its good to know these things and amazing you’re always on top of it @DodoNotDoDo

i didnt realize there was a 500mb limit, does this limit only applies to website uploading?

The limit is for both web and in-game publishing. I’m adding in better error messaging where I can. In some cases problems happen in systems outside my control so I’m not always able to provide better details without manual investigation. I’ll continue to look to make improvements though.


with 500MB, if someone were to make a mod with UHD this would quickly fill up given those large file size. possible to up this to 1GB?

@Yorok0’s been asking for that for a while too (or no limit). I’ll need to do some testing to be sure it won’t break anything, but in theory it should be do-able.


Good day sir. I thank you for your response and your assistance. But a few minutes ago I have attempted to upload my mod via the Microsoft/xbox site to no avail.

I know not if there is anything wrong with the mod from my end, all I know is that due to the scale of the mod, when you load it the first 2 to 5 times it causes the game to crash, but after that, the game seems to build a cash memory of the files, for after the game crashed 3 or 4 times, the game never crashed again and all the extensive testing I do on my mod in game works 100% . I have now played about 20 full single player games with different civs with no problems what so ever ,Before that I spent a considerable amount of time in the scenario editor testing each unit/building of each civ.

I hope we can make this work I would love to get to play Online Multiplayer with my friends using this mod. I thank you for your time.

I was able to recreate the issue. I’m working on resolving the problem and will let you know once it should work again.

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I thank you so much for your assistance. I have implemented some alterations/Fixes to the mod but allas it continues to fail with the upload.

I hope you are experiencing more progress than I am.

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Good day sir!! It seems that for some reason since I conducted my alterations that the mod did upload succesfully last night although it still says :Failed to upload the mod.

So I am so happy that it works.
All I need now, is to have the achievements of events as well as Steam achievements be achievable whilst visual dataset mods are active. But that is a discussion for another time.

I thank you for your aid and assistance ! God bless.

what happens when you try to upload in game instead of on website?

I have never been able to upload via website successfully, not a single time. in game however makes it so much easier.

Both in game as well as website it read :"error ,unable to upload mod. Check mod data. " But each time ,the mod was uploaded, regardless of the error message.

I have that too. a lot of times it keep failing me but data still uploaded. I keep uploading until the online files size/file count matches the one I have on my computer, then I run it to make sure it works.

@CelticKeeper sorry for the delay on this. In theory this should now work correctly on the web site as well. There was a part of the process that was causing a timeout but that should be remedied now. I just tested successfully myself but it would be great if you can confirm whether it works for you now.


Good day sir. I did manage to uploadt it succesfully. I thank you for your aid.

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