Mercury Transmit issue

Issue

Mercury Transmit fails to initialize at project startup unless the Lumetri Color panel exists in the startup workspace.

Key finding (reproducible):

Mercury Transmit fails to initialize at startup only if the startup workspace does not contain the Lumetri Color panel.

The Lumetri Color panel does not need to be visible or active.

Its mere presence as a background tab is sufficient to initialize Mercury Transmit correctly.

Once Mercury Transmit has initialized, the user can switch to any other workspace and the external output continues working normally.

The behaviour is reproducible with different projects, including newly created empty projects.

Environment

• Premiere Pro 26.3.0
• Windows
• NVIDIA GTX 1070 Mobile
• NVIDIA Studio Driver 581.57
• Clevo P775TM1
• Secondary HDMI monitor (Extended Desktop)
• Mercury Transmit enabled
• Adobe Monitor 2 selected for external playback

Issue

Mercury Transmit does not start automatically when opening a project if the startup workspace does not contain the Lumetri Color panel.

Mercury Transmit remains enabled, Adobe Monitor 2 is correctly selected, and Windows detects the external monitor correctly.

The issue is not related to monitor detection. Adobe Monitor 1 and Adobe Monitor 2 are correctly enumerated as soon as a project is opened. Only the external playback pipeline fails to initialize.

Steps to reproduce

1. Enable Mercury Transmit on Adobe Monitor 2.
2. Create a workspace without the Lumetri Color panel.
3. Close Premiere Pro.
4. Launch Premiere Pro.
5. Open any project.

Actual result

No external video output is displayed through Mercury Transmit.

Opening Preferences > Playback immediately initializes Mercury Transmit and external playback starts working.

Additional discovery

A reproducible workaround exists.

If the startup workspace contains the Lumetri Color panel, Mercury Transmit initializes correctly at startup.

The panel:

• does not need to be visible,
• does not need to be active,
• can simply exist as a background tab,
• can even be the only additional panel in the workspace.

Removing only the Lumetri Color panel from the workspace causes the issue to return.

Once Mercury Transmit has initialized successfully, it continues working even after switching to another workspace that does not contain the Lumetri Color panel.

Expected result

Mercury Transmit should initialize regardless of whether the Lumetri Color panel is present in the startup workspace.

Notes

This appears to be an initialization-order issue rather than a GPU or monitor detection problem because:

• Windows always detects the HDMI monitor.
• Adobe Monitor devices are correctly created.
• Mercury Transmit remains enabled.
• The issue only occurs during startup initialization.
• The Lumetri Color panel consistently triggers successful initialization.

Additional observations :

• Windows always detects the HDMI monitor.
• Adobe Monitor devices are created correctly.
• Mercury Transmit remains enabled.
• Playback Preferences immediately initialize the external output.
• A workspace containing only the Lumetri Color panel also initializes the external output.
• Removing only the Lumetri Color panel from the startup workspace makes the issue return.
• Once initialized, Mercury Transmit remains operational after switching to a workspace without Lumetri.