Transport Fever 3 Mods Not Working: Mod Hub, mod.io and Fix Steps

Decide which mod problem you have

This guide covers the Mod Hub that runs on mod.io. The launch build and both October stability updates were reviewed on 28 October 2026. We have not reproduced a mod failure in a running client.

Activate mods for each save

Subscribing in the Mod Hub downloads a mod; it does not switch it on.

• In the Add Mods tab when you create a new game, press Activate on each mod you want.
• For an existing save, check the save’s list of active mods under Load Game before assuming a mod is broken.

Mod Hub greyed out or login fails

Urban Games’ known-issues guidance says greyed-out main-menu buttons usually mean the game cannot reach your store platform or an online service the feature needs — and the Mod Hub runs online through mod.io.

• Check your internet connection, and make sure Steam, the Epic Games Store or GOG is running and signed in to the right account.
• Check for a platform or mod.io outage, then restart both the game and the launcher.
• If you use a mod.io account, sign in with the same account everywhere — logging in with a linked-but-different account will not show your subscriptions.

Error 20488 and the 6 October outage

On 6 October 2026 a global mod.io outage made the game report every subscription as removed, and some players saw error 20488. A developer confirmed the outage was on mod.io’s side and that collections re-downloaded once service returned.

• If this happens to you, wait and restart before reinstalling anything — reinstalling does not help with a server-side desync.
• The developer has said they are working with mod.io so future outages do not remove local subscriptions.

A mod crashes the game

• Disable all mods when loading the affected save, then log out of the Mod Hub and restart the game. If it still crashes, delete the shader_cache folder in your userdata folder.
• Update the mod in the Hub before removing it. Example: Urban Games flagged the popular Park and Ride mod for crashes; a mod update on 9 October resolved them, with minor errors possible while the author finishes a complete fix.
• Keep achievement runs mod-free: non-cosmetic mods and non-standard gameplay settings generally disable achievements.

Transport Fever 2 mods do not carry over

Mods must be made or updated for Transport Fever 3. Build 40420 fixed construction-menu errors caused by faulty mods and wrong terminal assignment for stops built on modded asymmetric streets, so keep the game itself updated too.

Manual installs on Steam go in userdata\…\3493540\local\mods; on GOG and Epic, in the mods folder under AppData\Roaming\Transport Fever 3. Mod Hub downloads live separately in C:\Users\Public\mod.io\10640\mods.