0xC0000409 STATUS_STACK_BUFFER_OVERRUN - crashes on all multiplayer...

0xC0000409 STATUS_STACK_BUFFER_OVERRUN - crashes on all multiplayer servers (official & private)

Multiplayer

State

Open

Issue key

A3G-57

Access

Public

Space

Arma 3

Project

General

Creator

opop156

Created

Sep 5, 2026

Views

Issue Type

Crash or Freeze

Section

Game Version

2.22 (Current Stable)

Was this also present in the previous version?

No, this is a new issue

Severity

I can't play with this

Section

Operating System

Windows

Windows Version

Windows 11

Description

After a completely clean reinstall (no mods, -mod= empty, confirmed in the attached rpt), the game crashes with 0xC0000409 STATUS_STACK_BUFFER_OVERRUN whenever I try to play on any multiplayer server — both official and private/community servers. Attached is the full troubleshooting report zip.

System: AMD Ryzen 7 7700, RTX 5060 Ti (driver 61656/r616_41), 31GB RAM, Version 2.22.154045.

Attachment1 file · visible to everyone

ArmaReport_Log_20260905T094633_XXX.zip

275 KB

Reactions

Activity

14 days ago

opop156
created issue14 days ago
opop156
14 days ago
opop156
14 days ago
Can confirm the same root cause on my end — my Windows username was in Chinese (non-ASCII), causing the exact same CTD (STATUS_STACK_BUFFER_OVERRUN) on loading into multiplayer servers, both official and private, on 2.22. No mdmp was generated either, matching this report.
After creating a new Windows account with an English-only username (so the profile path no longer contains non-ASCII characters), the crash is completely gone.
This confirms it's not Korean-specific — any non-ASCII character in the Windows username/filepath (e.g. C:\Users\<name>\AppData\Local\Arma 3\...) seems to trigger it. Hope this helps narrow down the exact code path.

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State

Open

Issue key

A3G-57

Access

Public

Space

Arma 3

Project

General

Creator

opop156

Created

Sep 5, 2026

Views

Can confirm the same root cause on my end — my Windows username was in Chinese (non-ASCII), causing the exact same CTD (STATUS_STACK_BUFFER_OVERRUN) on loading into multiplayer servers, both official and private, on 2.22. No mdmp was generated either, matching this report.

After creating a new Windows account with an English-only username (so the profile path no longer contains non-ASCII characters), the crash is completely gone.

This confirms it's not Korean-specific — any non-ASCII character in the Windows username/filepath (e.g. C:\Users\<name>\AppData\Local\Arma 3\...) seems to trigger it. Hope this helps narrow down the exact code path.