Hotfix - Patch 1.5.10f1
Cities: Skylines II Patch Notes — June 1, 2026
Aggregated from Steam, cross-tracked with Battle.net coverage on GamePatchNote.
This patch should not affect mods, and loading of old savegames is supported.
After our previous patch, we received a lot of reports about being unable to save, or receiving ‘NotSupportedException’ error. We want to thank everyone who participated in testing out the open beta branch that we released related to this issue!
We have prepared a hotfix that addresses the symptoms of this saving bug. Our research suggests that the actual issue was introduced by the addition of Asset Editor last year, but it stayed hidden until our recent change. We are still looking into the root cause of this issue and plan to release a complete fix for the bug in our next patch! However, in the meantime, the current fix should be enough to keep your game going and saves functioning.
Misc:
Fixed issue with saving old save games.
Fixed issue with saving custom maps.