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Stellaris 4.5.1 released (checksum 358e)

Paradox posted "Stellaris 4.5.1 released (checksum 358e)" as a Community Announcement on the Stellaris Steam page on Sep 24, 2026 (15:19 UTC). The text below is theirs, unchanged; the label "Patch notes" is ours, from the title.

The announcement

Paradox's text as published on Steam. Pictures stay on Steam's server; only their addresses are linked.

Picture in the original post: open on Steam's server

by Eladrin

Hello, Stellaris community!

We've updated Steam and GoG with a hotfix to address a few important issues. MS will follow as soon as it is possible.

4.5.1 ‘Cygnus’ Hotfix Release Notes

Balance

  • A Synaptic Lathe built by nomads in another empire's system no longer changes ownership to the owner of the Starbase.

    • Note: This is a quality of life balance change. In a future patch we are likely to give the owner of a system with a Synaptic Lathe some means to deal with it.

Bugfix

  • Fleet automation now follows the actions and options you select, instead of choosing for itself.

  • Removed the Harvesting Agreements Automation sub-menu setting, since the Trade Action has been removed

  • Disabled the auto-disengagement from battle when a ship didn't take part in combat for 15 days (ships disappearing from battle).

    • Note: This will return in a future release once we make it less overenthusiastic.

Stability

  • Fixed a very common Out of Sync that would occur after the first day of Multiplayer Games where custom AI empires were spawning.

We have taken the opportunity to bring in a number of other stability fixes that would otherwise have been in what’s now going to be 4.5.2:

  • Fixed a rare crash that could occur when joining an alliance.

  • Fixed a rare crash that could happen when a starbase automatically rebuilt its design after it changed level.

  • Fixed a crash during game startup caused by a technology that could not be resolved.

  • Fixed a crash during galaxy generation caused by a species with no assigned name data.

  • Fixed a crash that could occur when an empire joined a war.

  • Fixed a crash that could occur during first contact between empires.

  • Fixed a crash that could occur when accepting a federation law vote.

  • Fixed a crash that could occur when releasing a subject, or when a subject asked to be released.

  • Fixed a crash that could occur when a subject's overlord changed.

  • Fixed a crash that could occur when spending diplomatic weight on a galactic community resolution.

  • Fixed a rare crash when a waystation was destroyed after its controlling empire had already been eliminated.

  • Executing a spawn_natural_wormhole effect targeting an inexistent spatial reference object does not result in crashing the game any longer.

Modding

  • Duplicate keys in a database now always log an error.

Thank you for reporting these issues, and thank you for playing Stellaris!

On this site

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Source: store.steampowered.com/news/app/281990. Not affiliated with Paradox Interactive.

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