System tray failure causes 'Main loop has exited', preventing headless/server operation on Linux

[wintrover]

Environment

• Sunshine version: 2026.516.143833
• OS: Linux Mint 22.3 (Cinnamon X11)
• GPU: AMD Radeon iGPU (display) + NVIDIA RTX 3060 (PRIME offload)
• Kernel: 6.17.0-29-generic

Issue 1: System tray crash causes streaming to be unavailable

When running Sunshine without a system tray (headless/server context, or from a systemd user service), the "System tray is not initialized" error causes "Main loop has exited", which prevents the streaming server from fully starting. The web UI becomes partially functional but streaming never works.

Workaround found

Adding system_tray = disabled to ~/.config/sunshine/sunshine.conf fixes this ("No main thread features enabled, skipping event loop"), and streaming then works correctly. However, this option is not well-documented for headless/server setups.

Issue 2: KMS capture requires cap_sys_admin but systemd user services cannot apply ambient capabilities

• The Sunshine binary has cap_sys_admin,cap_sys_nice=p set via setcap
• However, when launched via a systemd user service, these capabilities are not carried through to the running process (CapEff=0000000000000000)
• Setting AmbientCapabilities=CAP_SYS_ADMIN CAP_SYS_NICE in a systemd user service override fails with "Operation not permitted"
• Workaround: Use capture = x11 instead of KMS (KMS capture not needed)

Issue 3: User needs video group for DRM access

The user must be in the video group to access /dev/dri/card*. Sunshine documentation does not mention this prerequisite.

Suggestions

1. Document that system_tray = disabled is required for headless/server setups
2. Document that the user must be in the video group for KMS capture
3. Consider adding a startup diagnostic that checks these prerequisites
4. Improve error messages to point the user toward the fix ("Missing video group membership? Missing capabilities?")

[ReenigneArcher]

Thanks AI

[darman84]

Issue 2 definitely needs to be documented somewhere. I have significantly higher host processing latency when using X11 instead of KMS on a system running Linux mint 22.3 with intel uhd graphics 630. I was able to find this workaround that solved the issue for me:
To fix Issue 2 and keep KMS capture, you need to run Sunshine as a system service. systemd user services cannot grant the required ambient capabilities.

Create /etc/systemd/system/sunshine.service and include this under [Service]:

[Service]
User=YOUR_USERNAME
ExecStart=/usr/bin/sunshine
AmbientCapabilities=CAP_SYS_ADMIN CAP_SYS_NICE

Then swap the services:

systemctl --user disable --now sunshine.service
sudo systemctl daemon-reload
sudo systemctl enable --now sunshine.service