[Guide] How to change the turn mode (Dynamic ↔ Simultaneous) of an existing Civ VI multiplayer save

Started a multiplayer game in the wrong turn mode and only noticed 190 turns in? The game won’t let you change it when you reload, but it’s a quick hex edit. This is the Civ VI version of the old Civ V trick.

Why it works: Civ V stored turn mode as readable text (GAMEOPTION_DYNAMIC_TURNS) followed by an on/off byte. Civ VI doesn’t store the setting names as text; it stores 4-byte codes (CRC32 hashes). I made two saves that were identical except for turn mode and compared them byte by byte. Turn mode is stored as one 4-byte value, written 3 times in each save, and all three copies are in the save’s uncompressed header. That means there’s no decompressing or recompressing, just a straight swap.

Turn mode	Hex value
Dynamic	4D B6 B3 9A
Simultaneous	BF B6 AB 9A

Steps:

1. Host saves the game locally and quits.
2. Find the save: Documents\My Games\Sid Meier's Civilization VI\Saves\Multi\. If your Documents folder is synced to OneDrive, look under OneDrive\Documents\... instead.
3. Make a backup copy of the save.
4. Open it in a hex editor. HxD is free on Windows; Hex Fiend works on Mac.
5. Search → Replace, with the search type set to Hex values:
   • Dynamic → Simultaneous: find 4DB6B39A, replace with BFB6AB9A
   • Simultaneous → Dynamic: the reverse
6. Replace all. You should get exactly 3 replacements. If you get a different number, stop and use your backup.
7. Save, then host → Load Game → launch.

Important: you’re overwriting bytes, not inserting them. The file size should stay exactly the same. If it grew, the save is corrupted, so start over from your backup.

Notes:

• Tested on game version 1.0.12.54 (Gathering Storm). The codes are hashes of the setting names, so they shouldn’t change between patches.
• I haven’t mapped Hotseat/Sequential yet. If someone saves two game configs that differ only in that setting (Host Game → Save Configuration) and compares them, it should show up the same way.
• This also works on .Civ6Cfg files from Save Configuration. Those have only one copy of the value.