Fix Forge startup before troubleshooting the browser
If the console closed or never printed a local URL, the browser is not the problem yet. Preserve the first console error, identify the last completed stage, and change only the layer that failed.
dfdcbabEvidence checked 24 Aug 2026The last completed stage decides the next test
“Forge will not open” describes several different failures. Use the earliest boundary you can prove.
Console closed
Keep the error visible and fix the first named component. No local page exists after the process exits.
Startup incomplete
Wait only while output changes. If it stops or errors, capture the last complete phase and traceback.
Test the address
Keep the console alive and open that exact URL manually. Browser autolaunch is optional.
Match the timestamp
Record the action, browser message, and same-time console error. Route by model, memory, extension, or request evidence.
This page gets the original Forge process and local interface to a stable state. If the first error names the interpreter, virtual environment, packages or accelerator, continue with the Python, Torch and CUDA diagnostic guide. Memory tuning, extension compatibility, and reverse-proxy deployment remain separate tasks.
What happened on this launch?
Choose the closest observable state. Do not select a presumed cause.
- What it means
- There is no local server for the browser to reach. “Press any key” is the Windows launcher pausing after launch.py returned; the useful cause is earlier in the console.
- Do this now
- Run the same launcher from a terminal that stays open. For the official package use cmd /k run.bat; for a Git checkout use cmd /k webui-user.bat. Save the first traceback, not only the last pause line.
- Capture
- Install route, Forge commit, launch arguments, first ERROR or traceback, Python/Torch/device lines, and whether this is the first run or a previously working folder.
Read the console as a sequence, not a wall of text
The first failure after a completed gate is more useful than the browser’s final summary.
- 01
Launcher
Batch or shell script starts PythonFailure here names Python, permissions, path, Git, pip, or environment creation.
- 02
Environment
Dependencies and imports prepareA first run can be active without a browser. Progress or download output means wait; an error means capture.
- 03
Device + extensions
Torch/device lines and scripts loadThe first extension traceback or accelerator error is more useful than a later browser symptom.
- 04
UI assembly
Forge creates the Gradio interfaceA process can still fail before the server is ready. No printed URL means the browser has nothing to open.
- 05
Local server
Gradio prints the current local URLKeep the process alive and use this exact address. Later failures must be tied to the action and console time.
The console remains running, prints Running on local URL: http://127.0.0.1:[port], and the same address refreshes while that process is alive.
Localhost is an address, not a cloud service
Current Forge passes server name, port, sharing, TLS, and subpath options into Gradio. Those controls change different boundaries.
Inspect the launch code ↗| Term | Meaning | Safe interpretation |
|---|---|---|
http://127.0.0.1:PORT | Loopback address on this computer | Open the exact value printed by the current console. Replace PORT only with the printed number. |
http://localhost:PORT | A hostname that normally resolves back to this computer | If it behaves differently from 127.0.0.1, record that fact; do not rewrite server settings blindly. |
7860, 7861, or another port | A numbered endpoint, not part of the product name | Never assume the port. Another process or an explicit --port value can change it. |
0.0.0.0 | A bind address used with --listen | It is not the normal address to paste into a browser. --listen permits network requests and changes the security boundary. |
--share | Requests a Gradio public sharing route | Not a localhost repair. Do not expose a troubleshooting session or private outputs merely to bypass a local problem. |
--server-name / --subpath / TLS | Advanced hosting and reverse-proxy controls | Return to a default local baseline before debugging proxy, hostname, subpath, or certificate configuration. |
One clean launch, without destroying the failing state
This comparison answers whether core Forge can reach its local server with default exposure and without third-party extensions.
- 01
Preserve the failure
Copy the launch arguments and save the complete console output. Do not update Forge, drivers, extensions, and packages together.
- 02
Keep the process observable
Start from a terminal that remains open. On the official Windows package use cmd /k run.bat; on a Git checkout use cmd /k webui-user.bat.
- 03
Remove exposure changes
For a local test, remove --share, --listen, custom server-name, proxy subpath, and TLS options unless one of them is the explicit subject of the test.
- 04
Isolate third-party extensions
Add --disable-all-extensions for one run. Current Forge defines this argument to prevent all extensions from running without deleting their folders.
- 05
Follow the newest printed address
If a local URL appears, keep that console open and manually open the exact URL. Test a private browser window only as a separate browser-state check.
- 06
Compare a separate clean install
If the same build works in a new folder, compare commits, arguments, config, environment, and extensions. Keep the failing folder for evidence.
cmd /k run.batcmd /k webui-user.batDeleting venv, replacing packages, or updating the whole folder before saving the error removes the comparison you need. Preserve, then test separately.
The phrase is real. The cause is not singular.
The official post is valuable evidence, but it is dated 24 August 2024 and groups several resource-heavy symptoms under one swap recommendation.
Read official discussion #1474 ↗What the maintainer documented
CPUAllocator, Killed, Error 1006, timeouts, slow model loading, and other crashes were routed to system swap. The post suggested at least 40 GB as a safe value for that 2024 context.
What remains the safe diagnostic rule
Use the first console error and failure stage. A disconnect while loading a large model is not equivalent to a blank page while the process stays alive, an extension import error, or a wrong local URL.
Match the message to its boundary
Open only the message you actually observed. Similar browser wording can hide different server states.
“Press any key to continue” is the last line
The Windows wrapper reached its pause after the Python launcher returned. Scroll upward or relaunch with cmd /k so the first failure remains visible.
“Couldn’t launch python”
The current Windows launcher could not execute the configured Python command. Verify the install route and PYTHON setting before touching Torch or browser options.
“Unable to create venv”
Environment creation failed before Forge could start. Record the target path, Python executable, permissions, free disk space, and stderr shown by the batch file.
Console is downloading and appears stuck on first run
First startup may prepare packages and assets. Continuing output or disk/network activity is not the same as a hang. Record the last changing line before interrupting.
No “Running on local URL” line appears
The server has not reached its done state. Diagnose the last console phase; reopening tabs or clearing browser cache cannot start it.
“Running on local URL” appears, but the tab does not
Autolaunch and server launch are separate in current code. Paste the printed URL manually while the process remains running.
ERR_CONNECTION_REFUSED at localhost
No server is accepting that exact address now. Confirm the process, current port, and newest URL before checking browser state or firewall rules.
The page remains on Loading after the URL appears
A post-launch callback, extension, browser request, custom URL/proxy setting, or unresolved Gradio/runtime problem may be involved. Test the default local path and extension-disabled core, then preserve the exact client and server errors.
“Connection errored out”, Error 1006, or Read timed out
These labels cover multiple failure stages. The official 2024 note routes many cases to system swap, but current diagnosis must still use the first console error, action, memory evidence, model, and environment.
Make the next report reproducible
Nothing here is uploaded. The checklist prevents a browser screenshot from replacing the process evidence.
Forge startup and localhost FAQ
Direct answers for common query wording, with network exposure kept separate from local recovery.
Why is Stable Diffusion WebUI Forge not opening?
First check the console. If the process closed or never printed a local URL, diagnose the first startup error. If the console is alive and printed an address, open that exact address manually.
How do I stop the Forge console from closing immediately?
On the official Windows package, open a terminal in the package folder and run cmd /k run.bat. For a Git checkout, run cmd /k webui-user.bat. This preserves the earlier error above “Press any key”.
What does “Press any key to continue” mean in Forge?
The Windows batch wrapper paused after the Python launcher returned. It is not the root error; the useful Python, dependency, model, memory, or extension message is usually earlier in the same console.
Why does Forge stay open but never show a local URL?
It has not completed the server-launch stage. It may still be preparing dependencies or building the UI, or it may be stopped by an error. Record the last changing line and the last completed phase.
What URL should I use to open Forge?
Use the exact local URL printed by the current Forge console, commonly in the form http://127.0.0.1:PORT. Do not rely on a saved port from another launch.
Why is Forge running but the browser did not open?
Browser autolaunch is separate from server startup in current Forge code. Leave the console running and paste its printed local URL into your browser.
How do I fix localhost refused to connect in Forge?
Confirm that the Forge process is still alive and that you are using the newest printed port. If the process exited or never printed a URL, fix the console error first; a browser cannot restart the server.
Does closing the Forge browser tab stop generation?
Closing only the tab does not normally stop the local process. You can reopen the printed URL while the console is running. Closing the Forge console normally stops the local server.
What does “Connection errored out” mean in Forge?
It means the browser lost a request or connection to the Forge process; it does not identify the cause. Correlate the message with the same-time console error and the action that preceded it.
Is 40 GB of system swap required for Forge?
The maintainer recommended at least 40 GB in an August 2024 troubleshooting post for a broad group of memory-related symptoms. Treat that as a dated recovery recommendation, not a universal modern requirement or proof that every disconnect is caused by swap.
Should I add --listen when localhost does not work?
No. --listen makes Gradio bind for network requests; it does not repair a crashed local process or wrong port and it changes who may be able to reach the UI.
Should I use --share to fix Connection errored out?
No. --share requests a public Gradio route and expands exposure. Restore the default local path and diagnose the console instead.
Why does 0.0.0.0 appear when I use --listen?
0.0.0.0 is a server bind address, not the normal browser destination. Use an appropriate local or LAN address only after deliberately configuring network access.
How do I start Forge without extensions?
Temporarily add --disable-all-extensions to the launch arguments. Current Forge code defines it to prevent all extensions from running; remove it after the isolation test.
Can an extension stop the Forge UI from opening?
Yes, an extension can fail while scripts or UI callbacks load. If the core UI starts with --disable-all-extensions, preserve the failing extension path and route the case to extension compatibility diagnosis.
Why does Forge disconnect when a model starts loading?
That is later than basic server startup. Record the model, last console line, RAM/VRAM evidence, and whether a base model works. Route an OOM or stall by the model-loading stage.
Why does the Forge page stay on Loading forever?
First check whether the process remains alive and whether the browser is requesting the exact printed address. Then compare a private window and an extension-disabled default local launch while saving both browser and console errors.
What if Forge prints Running on local URL and then throws another error?
The URL proves that Gradio launch returned, not that every later callback, extension, model load, or browser request succeeded. Use the first later traceback and the action at that timestamp.
Should I delete venv when Forge will not start?
Not as the first action. Record the environment and error first. A separate clean install or renamed, preserved environment gives a useful comparison; immediate deletion removes evidence and may not address the cause.
What should I include in a Forge startup bug report?
Include original-repository identity, Forge commit, install route, OS, GPU, RAM/VRAM, Python and Torch lines, launch arguments, exact action, newest local URL, complete console log, extension-disabled result, clean-install result, and reviewed Sysinfo.
Code mechanics, dated guidance, unresolved reports
Tutorials establish user vocabulary. Current mechanics come from original Forge code; issue reports remain reports until reproduced.
Current launch path
webui.py, cmd_args.py, initialization utilities, and the Windows launcher were inspected at commit dfdcbab.
Official 2024 recovery note
The swap and corrupted-model advice is preserved with its date and uncertainty. It is not rewritten as a universal requirement for every localhost symptom.
Inspect discussion #1474 ↗Different failures, similar screens
Open and closed reports show printed URLs followed by Gradio errors, malformed request URLs, or shared-environment extension failures. They identify branches, not guaranteed fixes.
Inspect recent issue #3137 ↗