Quick answer
Official rules confirmedOld worlds work. A fresh world is recommended—not required.
Keep your old world if preserving major builds matters most and you can seek new content in unexplored areas. Start fresh if you want the cleanest 1.0 experience. If you are unsure, preserve the old world and begin a separate new one.
Decision matrix
Choose the tradeoff you can live with
The official rule is simple; the personal cost is not. Choose whether your priority is the existing world, the lowest-regret compromise, or a complete fresh release experience.
Keep your old world
Best when the build matters more than a completely fresh 1.0 map.
- You want to preserve a long-built base and world history.
- You accept that new content generates properly only in unexplored areas.
- You can travel beyond generated territory for new world content.
Preserve, then restart
Best when you are undecided or share the world with other players.
- Keep an untouched backup of the world you care about.
- Create a separate fresh world for the complete 1.0 journey.
- Return later if preserving the build matters more than restarting.
Start a new world
Best when you want the cleanest, most complete 1.0 experience.
- You want each biome generated under the final release.
- Your old world already covers large areas near future content.
- You are comfortable rebuilding instead of protecting structures.
Confirmed by Iron Gate
The three rules that decide this
Old saves remain playable
The official 1.0 FAQ says old saves will remain and can be continued after the update.
Unexplored areas matter
New content is generated properly only in areas that have not already been explored.
Restarting is a recommendation
Iron Gate recommends starting from the beginning for the best experience. It does not say every player must delete an existing world.
Why explored areas change the answer
Valheim creates world content as you explore. If an area has already been generated, do not assume 1.0 will rebuild it with every new feature. The official wording supports planning around unexplored territory; it does not provide one universal safe-distance number or promise that a particular old location will regenerate.
If you explored widely and want the final release to shape the whole journey, restart. If an established base matters more, keep the world and treat distant, unvisited land as the place to seek newly generated content.
Character, achievement, and mod boundaries
Starting a new world does not make every other 1.0 decision disappear. The official FAQ says achievement tracking begins when you download 1.0, and its cheat rules can mark both a character and a world save. If achievements matter, keep cheat-enabled or experimental characters and worlds separate from the saves you want to use for achievements.
Iron Gate also says 1.0 has no official mod support and cannot guarantee that existing mods will work at launch. Preserve an unmodified copy before testing a valued modded world. This page does not recommend a world-upgrade mod or promise compatibility.
Before you choose
- 1
Preserve the current state
Make a recoverable copy before loading a valued world in a major update. Check your platform's save-management instructions before moving or replacing files.
- 2
Agree with your group
For a shared world, decide whether the group values its current build or a clean 1.0 journey before the host opens the save.
- 3
Keep mod experiments separate
If the world relies on mods, preserve the original and test separately. The official FAQ does not guarantee third-party mod compatibility.
What this guide does not claim
Old worlds are not confirmed to be broken, and the FAQ does not say explored areas will be erased. Unofficial world-upgrade tools are not guaranteed safe. Final Deep North layouts and any launch exceptions remain unknown before the 1.0 patch notes.
Version & sources
Sources & what may change
- Applies to
- Valheim 1.0 pre-release guidance
- Last verified
- September 4, 2026
- When to check again
- The September 9 patch notes may add exceptions for old worlds.