# Cities: Skylines II Hotfix - Patch 1.5.10f1

- Product: Cities: Skylines II (https://whatsnew.fyi/product/cities-skylines-ii)
- Vendor: Iceflake Studios
- Date: 2026-06-01
- Original notes: https://store.steampowered.com/news/app/949230/view/719032209192782079
- Permalink: https://whatsnew.fyi/product/cities-skylines-ii/releases/2026-06-01-hotfix-patch-1.5.10f1

What's New is an index, not a publisher: every entry below links to the vendor's own release notes, which are the authoritative source. Entries are labelled where they are hand-curated sample data, pre-releases, or drawn from a secondary source such as a developer blog.

Reuse: the summaries, labels and curation here are © What's New. Quote freely with attribution and a link back; wholesale republication of the corpus is not permitted — terms: https://whatsnew.fyi/terms. The vendors' own release notes remain their publishers'.

---

- **fixed** — Issue with saving old save games
- **fixed** — Issue with saving custom maps

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.