SimHub troubleshooting
Last updated · SimHub 9.11.22
Start from the symptom, not the subsystem. SimHub not starting is almost always missing .NET Framework 4.8 or a third-party plugin. A game not being detected is usually that it is not enabled in settings, or an admin-rights mismatch between the game and SimHub. An Arduino not appearing is usually a charge-only USB cable. A laggy dashboard is usually the GPU at over 90% load or adaptive sync interfering with rendering. Silent shakers are usually the wrong audio device or exclusive mode. A phone that will not connect is usually the firewall on port 8888.
Before anything else, two moves fix a disproportionate share of problems: disable third-party plugins, which the official troubleshooting page names as the leading cause of SimHub instability, and restart SimHub, which is required after some changes rather than being generic advice — a changed COM port is the clearest example.
Start here: what is it doing?
| Symptom | Most likely cause | Go to |
|---|---|---|
| SimHub won't start, or hangs on the splash screen | Missing .NET Framework 4.8, or a third-party plugin | SimHub won't start |
| SimHub runs but shows no telemetry | Game not enabled, or admin-rights mismatch | Game not detected |
| Arduino or USB device not listed | Charge-only USB cable | Arduino not detected |
| Worked until you opened CrewChief or another app | Only one application can receive a UDP stream | UDP conflicts |
| Dashboard stutters, or the game loses FPS | GPU above 90% load, or adaptive sync | Dashboard performance |
| Bass shakers silent or intermittent | Wrong audio device, or exclusive mode | Shakers silent |
| Phone or tablet will not load the dashboard | Firewall blocking port 8888 | Phone won't connect |
| SimHub.exe vanished, or antivirus flagged it | False positive — it reads UDP, TCP and shared memory | Antivirus and SimHub |
The three things to try before anything specific
- Disable third-party plugins. The official troubleshooting page names them as the number one cause of SimHub instability. This is the first diagnostic step, not a last resort, and it costs nothing to test — if the problem goes away, re-enable them one at a time.
- Restart SimHub. Some changes are not picked up live: a COM port that Windows reassigned, a port number changed in settings, a newly installed plugin. This is not generic advice, it is a real requirement in specific documented cases.
- Check you are on a current version. SimHub ships frequently. This cluster is checked against 9.11.22; several releases landed in the weeks before it.
SimHub won't start
The characteristic failure is a hang at Initializing: CoreData with no error dialog. That is .NET Framework 4.8 missing — install it and restart.
If .NET is present, suspect a plugin. Failing that, climb the reset ladder in order, and read the warning on the second rung before you get there.
Local User Settings Reset deletes your licence.It clears %localappdata%, which is where the licence lives alongside your settings, profiles and dashboards. Back that folder up before running any reset. Full details on the dedicated page.
SimHub runs but sees no telemetry
Four causes cover almost all of it:
- The game is not enabled in SimHub's settings. Only games you tick are watched.
- Admin rights do not match. If the game or its launcher runs as administrator, SimHub must too — a non-elevated process cannot read an elevated one's shared memory. This is the cause people find hardest to guess.
- A per-game step is missing. iRacing needs
irsdkEnableMem=1; Euro Truck Simulator 2 and American Truck Simulator need SimHub's telemetry plugin installed into the game. - Something else has the UDP stream. Only one application can receive it — see below.
It stopped working when you opened another app
This is worth its own entry because the symptom is confusing: everything worked, you opened CrewChief or Track Titan or a second dash application, and SimHub went blank.
A UDP stream can only be received by one application. Games that broadcast telemetry over UDP — the Forza titles, the Codemasters and F1 games, Project CARS, Gran Turismo — send to one port, and whichever app claims it first gets it. The second app gets nothing.
The fix is UDP forwarding: SimHub can re-broadcast what it receives to other ports and IP addresses, so it takes the stream and passes it on. The dedicated page covers the setup.
Dashboards lag, or the game loses frames
Usually not the dashboard itself. In rough order:
- The GPU is already at 90–95% load. SimHub renders with WPF, which is GPU-accelerated, so it is competing with the game for the same resource. An FPS limiter in the game is the first thing to try.
- Adaptive sync. G-Sync and FreeSync interfere with how SimHub renders. Set adaptive sync to fullscreen-only, or add a SimHub exception.
- Mismatched monitor refresh rates across a multi-monitor setup.
- Process throttlers. Windows Game Mode, Process Lasso, Norton Game Optimizer and MSI's X3D Mode all deliberately starve non-game processes — which is exactly what SimHub is.
- Oversized overlays. A transparent area still costs you; overlay surfaces are capped at 480,000 pixels for this reason.
There is also an alternative HTML rendering engine selectable per dashboard, which is worth trying when one specific dashboard misbehaves and others do not. Full detail on dashboard performance.
Gathering diagnostics before you ask for help
If you are going to ask someone else, arrive with these — it is the difference between an answer and twenty questions.
- The System Informations page inside SimHub. It reports your version, .NET, hardware and detected devices in one place.
- Your SimHub version, exactly. "The latest" is not a version; releases land often enough that it means nothing a week later.
- The game, and how its telemetry works — UDP, shared memory, or a SimHub-installed plugin. The games index explains which is which.
- What changed. Windows update, new plugin, new hardware, moved USB port. Something almost always did.
Where to get help
Discord is the primary channel now.Registration on the SimHub forum has been paused because of spam, so the forum is largely read-only for newcomers. It remains an excellent archive — searching it is often faster than asking — but if you need to ask a question, Discord is where people are.
- The official wiki — 71 pages, and the best reference for Arduino wiring. Written for people who already know the architecture.
- The SimHub forum — read and search freely; the Dashboard Templates section alone runs to nearly 1,900 posts.
- GitHub issues on
SHWotever/SimHub— around 388 open at the time of writing, and often the only place a specific bug is acknowledged.
Everything in this section
- Arduino not detected Cables, the generic CH340G driver break, COM ports, scan settings, power and unsupported boards.
- Game not detected Enabling games, admin-rights mismatches, per-game plugins and firewall rules.
- UDP conflicts with CrewChief Why only one app gets the stream, and how UDP forwarding fixes it.
- SimHub won't start The CoreData hang, plugin faults, and the reset ladder that deletes your licence.
- Antivirus and false positives Why Defender flags it, and the fix ladder that does not involve turning your antivirus off.
- Bass shakers silent Audio device, exclusive mode, enhancements, Voicemeeter and the 48kHz requirement.
- Dashboard lag and FPS drops GPU load, adaptive sync, process throttlers and the alternative rendering engine.
Common questions
What is the first thing to try when SimHub misbehaves?
Disable third-party plugins. The official troubleshooting page names them as the leading cause of SimHub instability, which makes disabling them a first diagnostic step rather than a last resort. Re-enable them one at a time to find the culprit.
Why does SimHub hang on "Initializing: CoreData"?
Missing .NET Framework 4.8. There is no error dialog — it simply stops at that line. Install .NET 4.8 from Microsoft and restart.
Why did SimHub stop seeing telemetry when I opened CrewChief?
For UDP-based games, only one application can receive the stream. Whichever claimed the port first gets it. The fix is SimHub's UDP forwarding, which takes the stream and re-broadcasts it to other ports and IPs so both apps work.
Do I need to run SimHub as administrator?
Only if the game or its launcher runs as administrator — then SimHub must too, because a non-elevated process cannot read an elevated one's shared memory. If nothing is elevated, do not elevate SimHub either.
Is the SimHub forum still active?
It is readable and searchable and holds a large archive, but registration is paused because of spam. Discord is the primary support channel now.
Does resetting SimHub delete my dashboards?
The Local User Settings Reset does — it clears %localappdata%, which holds your settings, profiles, dashboards and your licence. A Light Reinstall does not. Always try the Light Reinstall first, and back up %localappdata% before going further.
How do I find out which SimHub version I am on?
The System Informations page inside SimHub reports it, along with your .NET version and detected devices. Quote the exact version when asking for help — SimHub releases often enough that "the latest" is meaningless within a week.
My Arduino worked yesterday and does not today, and I changed nothing.
Check the driver. A Windows Update driver — CH341SER 3.8.2023.2 and later — breaks generic CH340G chips, and it arrives on its own. Device Manager showing "CH340" rather than "CH340G" confirms it.
Why does my dashboard stutter when the game is running fine?
SimHub renders through WPF on the GPU, so it competes with the game. If the GPU is above 90% load there is nothing left for it. Cap the game's frame rate first; then check whether G-Sync or FreeSync is interfering.
Can I recover a licence I deleted with a reset?
Yes — the licence email is the route back. Keep it. Better still, back up %localappdata% before running any reset, because that folder also holds every dashboard and profile you have set up.
Sources
Related guides
SimHub is developed independently by Wotever and is not affiliated with oesimracing. This page was checked against SimHub 9.11.22 on 4 August 2026; where the interface has moved on since, the version stamp tells you how far. More on what SimHub is and what it costs.