Valheim developer Iron Gate is advising all players backup their characters and worlds after discovering a "world-destroyer" bug is resetting progress.
In a tweet, CEO Richard Svensson explained how players can make backups and avoid losing their data to the bug, confirming that despite trying to reproduce it and address the glitch, the team hasn't yet been able to do so. However, Iron Gate suspects it may be connected to exiting the gaming by ALT+F4 and not via the menu.
"If you are playing Valheim this weekend, please backup your world and characters," Svensson said. "The evil world-destroyer bug is still roaming free =(.
"It's an evil bug, that we have yet to be able to reproduce even once :(. It seems to occur more often if you exit the game by ALT+F4, so try to use menu->exit instead."
To make a backup, Svensson advises you head to C:\Users\Username\AppData\LocalLow\IronGate\Valheim\" and copy the files (thanks, PC Gamer).
Valheim has sold over 1m copies in just a week. The Viking-themed survival and crafting game launched as an Early Access title on 2nd February, and quickly rose to the upper echelons of Steam and Twitch. It hit a peak of 160,000 concurrent users on Steam, and had over 127,000 peak viewers on Twitch during its first week on sale.