Developer Tools Not Visible After Detaching on macOS

[lmoronil]

Hello,

I'm experiencing an issue with Microsoft Edge on macOS (Version 140.0.3485.81 (Official build) (arm64)).
After detaching the Developer Tools window, it no longer appears on screen when I try to open it again. The page layout changes (e.g., device simulation activates), indicating that DevTools is running, but the window itself is not visible.

• Asked support on https://learn.microsoft.com/en-us/answers/questions/5565014/developer-tools-does-not-show-up-on-ms-edge-on-mac
• Verified that DeveloperToolsAvailability policy is not restricting access (edge://policy)
• Tried opening DevTools in Incognito mode (Cmd + Shift + N) — same issue
• Reset Edge settings via edge://settings/reset
• Reinstalled Edge completely
• Ran the following command in Terminal to reset DevTools window position and restarted Edge

defaults delete com.microsoft.edgmac DevToolsWindowBounds

2025-09-25 22:20:21.873 defaults[68940:41223172] 
Domain (com.microsoft.edgemac) not found.
Defaults have not been changed.

• Ran the following command to check defaults

defaults read com.microsoft.edgemac 

{
    LastRunAppBundlePath = "/Applications/Microsoft Edge.app";
    LoginKeychainEmpty = 1;
    NSNavPanelExpandedSizeForOpenMode = "{800, 448}";
    NSNavPanelExpandedSizeForSaveMode = "{800, 448}";
    NSNavPanelExpandedStateForSaveMode = 1;
    NSOSPLastRootDirectory = {length = 748, bytes = 0x626f6f6b ec020000 00000410 30000000 ... 8c010000 00000000 };
    "NSWindow Frame NSNavPanelAutosaveName" = "356 248 800 448 0 0 1512 944 ";
    OptionalDataCollectionEnabled = 0;
}

System Info:

macOS version: Version 15.4.1 (24E263)
Edge version: 140.0.3485.81 (Official build) (arm64)

Attachments:

Screenshot showing the page layout change without DevTools visible

Please advise on how to restore visibility of the detached Developer Tools window or reset its state.
Best regards

[lmoronil]

I've noticed that only my work profile suffers the issue, my personal profile Dev Tools works as expected.

Then I've tried to launch Edge from the terminal to check if any log is printed.

What I have noticed is that work profile print an error when trying to open dev tools:

[1525:46474075:0929/163839.477056:ERROR:CONSOLE:1] "Request Emulation.setEmitTouchEventsForMouse failed. {"code":-32601,"message":"'Emulation.setEmitTouchEventsForMouse' wasn't found"}", source: devtools://devtools/bundled/core/protocol_client/protocol_client.js (1)

Can be helpful?

[leahmsft]

Sorry you're experiencing this bug. Thank you for the detailed report, our team will start looking into this. In the meantime, can you please go to edge://flags and disable the #edge-rounded-containers flag and let me know if you still see the issue?

[SunsetTechuila]

I have a similar issue on Windows 11, so it's probably not OS-specific.

For me, the problem is that the DevTools preferences are out of sync with each other. devtools.currentDockState changes, but devtools.preferences.EdgeDevToolsLayoutInfo.current_dock_state does not. This causes the browser to display a panel even if DevTools are undocked or not display it even if they are docked, which makes them inaccessible.

I'm using MS Edge version 142.0.3595.11 (Official build) Beta (64-bit).

I've reproduced the issue in the Windows Sandbox as well.

[SunsetTechuila]

disable the #edge-rounded-containers flag

This fixes the issue

[leahmsft]

@SunsetTechuila thank you for your report. I'll share these details with the team.

[SunsetTechuila]

This causes the browser to display a panel even if DevTools are undocked

Here is how that looks:

[leahmsft]

@SunsetTechuila Ah yes, this is a known issue that our team is already looking into. Please use the workaround for now. It was also reported here: #378

@lmoronil it sounds like the issue you're having is that DevTools doesn't appear at all? Can you let me know if disabling the flag does anything?

[SunsetTechuila]

it sounds like the issue you're having is that DevTools doesn't appear at all?

or not display it even if they are docked, which makes them inaccessible.

If your preferences file ("%localappdata%\Microsoft\Edge\User Data\Default\Preferences") has devtools.preferences.EdgeDevToolsLayoutInfo.current_dock_state set to 3 (hiding the panel in browser) and devtools.currentDockState set to anything other than undocked (opening DevTools in a panel), the window won't appear. This is what happened to me.

[golf1052]

I just experienced this issue on Windows. The "disable the #edge-rounded-containers flag" workaround worked for me.

Edge Version: Version 142.0.3595.19 (Official build) beta (64-bit)

Windows version
Edition Windows 11 Enterprise
Version 25H2
OS build 26200.6899
Experience Windows Feature Experience Pack 1000.26100.253.0