Diablo IV: 3.1.0 patch (June 30, 2026) breaks launch on Linux - deliberate BREAKPOINT in diablo_iv_loader.dll

protonclosed

ValveSoftware/Proton#9926 · opened 2026-06-30 by oliverzein · updated 2026-06-30 · 3 comments · github

Ooliverzein 2026-06-30 github

Compatibility Report

Name of the game: Diablo IV
Steam AppID: 2344520 (also run via Battle.net as non-Steam game, appid 2177747739)
Date of regression: June 30, 2026 (patch 3.1.0 Build #72578, Season 14)

System Information

GPU: AMD Radeon RX 9070 XT (RDNA4)
Video driver: RADV (Mesa)
Kernel: CachyOS Linux 7.1.1
Proton versions tested: proton-cachyos 11.0.20260602, GE-Proton10-30, GE-Proton11-1 (Proton 11 bleeding-edge)
Launcher: Battle.net (added as non-Steam game)

Symptoms

Game crashes immediately on launch, before reaching the title screen. Identical crash across all 3 Proton versions tested.

Reproduction

Install D4 via Battle.net under Proton
Launch after the 3.1.0 patch (June 30, 2026)
Game exits with Blizzard crash handler showing BREAKPOINT in diablo_iv_loader.dll

Crash details

Blizzard crash dump (errors/<timestamp>/Crash.txt):

<BlizzardError.Summary:>
BREAKPOINT
<:BlizzardError.Summary>
Thread 0x00000138 "Main Thread"
DBG-ADDR<00006FFFFC034A05>("diablo_iv_loader.dll")
DBG-ADDR<00006FFFFB3F95C6>("diablo_iv_loader.dll")
DBG-ADDR<00006FFFFFF20B64>("ntdll.dll")

Wine log (PROTON_LOG=1) shows the breakpoint fires at a fixed offset in diablo_iv_loader.dll:

warn:seh:dispatch_exception backtrace: --- Exception 0x80000003.
warn:seh:virtual_unwind backtrace: 00006FFFF8A04A05: L"diablo_iv_loader.dll" + 0000000000EE4A05.
warn:seh:virtual_unwind backtrace: 00006FFFF7DC95C6: L"diablo_iv_loader.dll" + 00000000002A95C6.

The breakpoint fires immediately after diablo_iv_loader.dll loads, right after this wine stub:

fixme:ntdll:NtQuerySystemInformation info_class SYSTEM_PERFORMANCE_INFORMATION

The offset 0x00EE4A05 is identical across all 3 Proton versions (proton-cachyos, GE-Proton10-30, GE-Proton11-1) and across multiple launches — indicating a deliberate __debugbreak() in the new loader, not a crash from a missing function.

The loader binary contains the strings Linux, BREAKPOINT, Press Cancel to break to debugger — strongly suggesting a deliberate anti-wine/anti-Linux detection check added in the 3.1.0 patch.

What I tried (none worked)

OptiScaler disabled (renamed dxgi.dll) — same crash
HideWineExports registry key (HKCU\Software\Wine\HideWineExports=y + AppDefaults for Diablo IV.exe) — same crash
dstorage.dll renamed (DirectStorage disabled, per Blizzard forum fix for loader crashes) — same crash
3 Proton versions (proton-cachyos 11.0, GE-Proton10-30, GE-Proton11-1/Proton 11) — same crash at identical offset

Analysis

This appears to be a new anti-tamper/anti-wine check introduced in the 3.1.0 patch (June 30, 2026). The loader detects the wine environment (likely via the SYSTEM_PERFORMANCE_INFORMATION stub returning non-Windows-like data, or another vector) and hits an intentional __debugbreak().

No current wine-staging or Proton patch bypasses this. The patch is hours old at the time of filing.

Logs

Wine log: attached as steam-2344520.log excerpt above
Blizzard crash dump available on request

References

Patch notes: https://news.blizzard.com/en-us/article/24287406/diablo-iv-patch-notes (3.1.0 Build #72578 — June 30, 2026)
OptiScaler wiki notes D4 has anticheat that detects unsupported software: https://github.com/optiscaler/OptiScaler/wiki/Diablo-4
REFramework uses similar wine_get_version detection bypass pattern: https://github.com/bakisama/REFramework/commit/0cf9e0dbcafbe3d2c860b4c763a7ff3e2b6f3957

Generated with Devin

Ooliverzein 2026-06-30 github

Update: Confirmed Linux-wide, all Proton versions

This is not isolated to my setup. Confirmed across multiple users/distros/GPUs/Proton versions in the Steam discussion:

Steam discussion: https://steamcommunity.com/app/2344520/discussions/0/565912926113803146/ (43+ reports and growing)

Confirmed affected configurations

Steam Deck (multiple users)
CachyOS + RTX 5080 (Geecrumb)
CachyOS + Steam Deck, Proton GE11.1 / 9.04 / cachy11 (Myrytox2)
CachyOS + RX 9070 XT, proton-cachyos / GE-Proton10-30 / GE-Proton11-1 (my report)

Identical crash signature from another user

Dr PicklePuncher posted the same crash dump in the Steam discussion:

<BlizzardError.Summary:>
BREAKPOINT
<:BlizzardError.Summary>
Thread 0x00000150 "Main Thread"
DBG-ADDR<00006FFFFB2D4A05>("diablo_iv_loader.dll")
DBG-ADDR<00006FFFFA6995C6>("diablo_iv_loader.dll")
DBG-ADDR<00006FFFFFF20B64>("ntdll.dll")

Same BREAKPOINT in diablo_iv_loader.dll, same call pattern — confirming the deliberate __debugbreak() at fixed offset 0x00EE4A05 in the new 3.1.0 loader.

User quote

"Not starting on any linux meanwhile. Seems to be a problem in a specific dll where the Launcher of D4 just aborts the call." — Sarimae

This is a regression introduced by the 3.1.0 patch (June 30, 2026, Season 14) affecting all Linux/Proton users. No current Proton version bypasses it.

Generated with Devin

XxXSythXx 2026-06-30 github

Heads up this is not a duplicate post at all and has nothing to do with the sleep functionality. The game flat out doesn't launch. Issue should be re-opened.

SSteveFoxx 2026-06-30 github

This appears to be a new regression introduced by the June 30, 2026 Diablo IV patch rather than the original 2023 issue.

Environment:

CachyOS (fully updated)
AMD RX 7900 XTX (RADV)
Mesa 26.1.3
Battle.net via Faugus/UMU
Reproduced with Proton-CachyOS 11, GE-Proton Latest, UMU-Proton Latest, Proton-EM Latest and DW-Proton Latest.

Behavior:

Battle.net launches successfully.
Clicking Play changes to Launching Playing Play again.
Diablo IV.exe is launched successfully by Battle.net, remains alive for ~9 seconds, then exits without creating a game window.
WoW and Diablo II: Resurrected continue to work from the same Battle.net prefix.

Battle.net log:

LaunchBinary: uid=fenris
Launched .../Diablo IV.exe
...
Game is no longer running: fenris

steam-default.log shows DXVK initializing for Battle.net.exe only. There is no initialization for Diablo IV.exe (no VKD3D/D3D12 startup, no Wine crash dialog, no visible exception), suggesting the game exits very early after process creation.

This started immediately after the June 30 game update and is reproducible across multiple Proton runners, which suggests a new compatibility regression rather than a launcher or distribution-specific issue.