Arma 3 Steam Query data overflow

Arma 3 can log this warning in the console and in the .rpt file:

Warning: Steam Query data overflow, Mods/Signatures will not be correctly received by clients. Remove unused mods or change your server configuration to allow for more data to be sent

Steam's server query protocol only sends a limited amount of data per response. When your server runs a lot of mods, the list of mods and signatures no longer fits, so clients receive an incomplete list. There are two fixes, and they combine well: trim the mod list, and raise the data limit.

1Remove Unused Mods (Fixes the Cause)

The warning literally asks you to remove unused mods, and the panel makes that easy:

• In the game panel, open your server and click Arma 3 Manager in the left menu under GAME SERVER.
• On the Mods tab, remove any mods your missions no longer need with the remove button on the right of each mod.
• A Restart required banner appears; press Restart server when you are done, or restart later.

While you are there, the Disk Cleanup tab deletes leftover mod folders from old mod packs. That frees disk space, but only mods removed from the active mod list shrink the query data.

2Raise the Steam Query Data Limit

If you need every mod on the list, allow Arma to send more data per query instead:

• Open Files in the left menu (see the file manager guide).
• Open server.cfg in the root of your server files.
• Add this on its own line:

steamProtocolMaxDataSize = 2048;

• Save the file and restart your server.

The panel's Arma 3 Manager only ever rewrites its own entries in server.cfg, so this line stays in place when you change other settings later. If the warning comes back after adding even more mods, raise the value another step.

Finished

After the restart the warning should be gone from the console and your clients receive the full mod and signature list again. Still seeing it? Trim the mod list further on the Arma 3 Manager page or raise steamProtocolMaxDataSize a bit more.