Compatibility Report

• Name of the game with compatibility issues:
• Battle.net launcher

System Information

• OS: Ubuntu 26.04 LTS (x86_64)
• GPU: NVIDIA GeForce RTX™ 5070 Laptop GPU and AMD Radeon™ 890M Graphics
• Driver Version: NVIDIA-SMI 595.71.05
• Kernel Version: 7.0.0-15-generic
• Proton Version: Tested on Experimental, GE-Proton10-34, and Proton 8.0 and Proton 9.0

Symptoms

Since upgrading to Ubuntu 26.04, launching the Blizzard Battle.net client as a non-Steam application results in a hang/deadlock before/if the UI initializes. It worked fine on 25.10.

Diagnostics & Log Analysis

Running with PROTON_LOG=1 isolates two distinct blocking behaviors:

1. Steam IPC / Overlay Failure: gameoverlayui crashes completely during initialization due to host-side glibc differences on Ubuntu 26.04. This breaks the overlay pipe, drops minidumps, and leaves zombie Wine processes in memory.
2. Blizzard Agent Race Condition: Immediately following the fixme:thread:NtSetInformationThread ThreadPowerThrottling stub! warning, the Blizzard Agent binary enters an unhandled loop throwing thousands of micro-exceptions via NtGetContextThread. The process hangs indefinitely until an internal 15-minute timeout forces a thread state flush.

Steps to Reproduce

1. Add Battle.net Installer/Launcher as a non-Steam game on Ubuntu 26.04.
2. Set launch arguments for Nvidia offloading: __NV_PRIME_RENDER_OFFLOAD=1 __GLX_VENDOR_LIBRARY_NAME=nvidia %command%
3. Launch the application. Observe the system hang with high micro-exception overhead in logs.

System Information

• GPU: NVIDIA GeForce RTX™ 5070 Laptop GPU and AMD Radeon™ 890M Graphics
• Driver Version: NVIDIA-SMI 595.71.05
• Kernel Version: 7.0.0-15-generic

• Link to full system information report as [Gist](https://gist.github.com/andrewsuperlegit/8d3bad2c96077f44443102b4bbdeef61

Here's the log output; i force quit it after a few minutes but i can run it for way longer if you'd like or if itd be helpful:

steam-13043138864154148864.log

):

• Proton version:

I confirm:

• [x] that I haven't found an existing compatibility report for this game.
• [x] that I have checked whether there are updates for my system available.