Cities: Skylines 1: Test a Mod-Related Save Failure Safely

Protect the city before testing

A load failure is not enough evidence to delete the save. Paradox's support flow starts by disabling mods and Workshop assets to see if the symptom changes. Record the exact game branch/version, operating system, city name, DLC and subscribed content so the comparison can be repeated.

1. Exit the game and make a second copy of the affected save somewhere outside the game's save directory.
2. Write down the current game version and whether the problem began after a game patch, mod update, asset addition or branch switch.
3. On Steam, open the original Cities: Skylines Properties and use Paradox's documented `--disableMods --noWorkshop` launch options for one test.
4. Try loading the same copied city. Record whether it reaches the city, stalls at the same point or shows a different error.
5. If it loads, treat mods/assets as a likely branch to investigate; do not overwrite the untouched backup.

References: Paradox Support: Save does not load / mods cause errors

Interpret the isolation test

References: Paradox Support: Save does not load / mods cause errors · Paradox Support: Cities won't launch or crashes after launch

Restore content without risking the only copy

Paradox's article describes unsubscribing and removing Addons only after the no-mod test. If you choose to clean a mod set, first copy the Addons folder and note subscriptions. Community mod lists are user-maintained and may be stale; verify each asset's current compatibility and author update date.

1. Keep the test launch option while you compare; change one batch of content at a time.
2. Back up the local Addons folder before any removal, as Paradox explicitly recommends.
3. After identifying a suspect, check its current author page and compatibility notes before enabling it again.
4. If the issue persists with no mods, submit the reproducible steps and relevant log through official support; do not attach a public city save unless support requests it.

References: Paradox Support: Cities won't launch or crashes after launch · Cities: Skylines player discussions

Before you play

• I backed up the city separately before loading it again.
• I confirmed this is Cities: Skylines (2015), not Cities: Skylines II.
• I tested the exact city once with Paradox's documented no-mod options.
• I preserved the Addons folder before cleanup.
• I recorded version, OS, DLC and mod changes without treating forum posts as confirmed fixes.

Frequently asked questions

Sources & revision notes

Editorial revision: November 6, 2026; not a gameplay test date. The reference notes identify source limits and version differences.

1. Paradox Support: Save does not load / mods cause errors (Official)

   Paradox's Cities: Skylines (2015) support article, updated May 17, 2026. It recommends testing Steam launch options --disableMods --noWorkshop before removing mods and says to back up Addons. Not applicable to Cities: Skylines II.

2. Paradox Support: Cities won't launch or crashes after launch (Official)

   Legacy Cities: Skylines (2015) PC troubleshooting, updated November 3, 2026. It describes mod/Workshop isolation and collecting output_log.txt; follow current support instructions and preserve saves.

3. Cities: Skylines player discussions (Community)

   External Steam topics are user-generated and may refer to old mods, builds or DLC. They are leads, not verified fixes; never upload a private city save publicly.