Brave/Chrome has no connectivity in sandbox (fine when unsandboxed)

[e-t-l]

Brave is installed on the host, and I noticed recently when I ran it in its usual sandbox, it was failing to load, throwing errors, or loading with no extensions or other user settings (I have NOT been getting the same errors as #5129, but I don't know for sure if my issue is totally unrelated. I tried their fixes but it didn't work. I don't even see any Brave elevation service installed).

Because of these problems, I ended up fulling uninstalling Brave and creating a new sandbox, then copying over my old sandboxed User Data directory. It loads just fine while unsandboxed now, but in the sandbox, although it will launch with all my old extensions etc loaded, it seems to have no network connectivity. Navigating to any website in sandboxed Brave just loads endlessly, freezes, or shows the browser ERR_ADDRESS_INVALID message. When I check my firewall (Portmaster), I don't even see any network requests from sandboxed Brave, which is strange.

I have confirmed there are no settings in Brave, in Sandboxie, in Portmaster, or in my Windows settings that would block its connectivity. Before I open a full bug report about this, does anyone have any suggestions?

[anntnzrb]

VERIFIED Fix: Add to Sandboxie.ini under your sandbox:

RpcMgmtSetComTimeout=n

Target specific browsers:

RpcMgmtSetComTimeout=brave.exe,n
RpcMgmtSetComTimeout=chrome.exe,n

Additional fix for installer issues:

ClosedClsid={4991D34B-80A1-4291-83B6-3328366B9097}

Why: The RpcMgmtSetComTimeout setting controls RPC communication timeout. When enabled (default), it causes network operations in Chromium browsers to fail. Disabling it restores normal connectivity.

Tested: This fix was confirmed by multiple users in issues #437, #5129 for Chrome, Brave, and Adobe Creative Cloud.

Reference: Sandboxie/install/SbieSettings.ini documents the RpcMgmtSetComTimeout setting.

[e-t-l]

Awesome, thank you! Strangely, just changing that config didn't work in my original sandbox (yes I terminated all programs in it to make the config take effect). But creating when I copied the config to a newly created box, it worked! No idea why, guess something was corrupted in my old box. But this is definitely the solution, since before this fix Brave wouldn't work even in a new empty box. Thanks!

[sislamoglu]

That didn't resolve issue with Firestorm Viewer that uses embedded CEF aas media plugin.