SimHub won't start
Last updated · SimHub 9.11.22
A SimHub that hangs at "Initializing: CoreData" is missing .NET Framework 4.8 — install it and restart. A SimHub that crashes or misbehaves after previously working is most likely a third-party plugin, which the official troubleshooting page names as the leading cause of instability. If neither applies, climb the reset ladder in order: Light Reinstall, then Local User Settings Reset, then Full Reset. Back up %localappdata% before the second step, because it deletes your licence along with every dashboard and profile you have.
The order here matters more than usual, because the second rung of the reset ladder is destructive and people reach it by following advice that did not mention that.
Hanging at "Initializing: CoreData"
The characteristic symptom: SimHub launches, the splash screen appears, it prints Initializing: CoreData, and stops. No error, no crash, no dialog — it simply waits forever.
This is .NET Framework 4.8 missing. Install it from Microsoft and restart the machine.
Why it hangs rather than erroring. The application starts using the parts of .NET that are present, and stalls when it reaches something that is not. There is no code path for "the framework I am running on is incomplete", so there is nothing to report. This is why the symptom gives you nothing to search for — which is exactly why it is at the top of this page.
Windows 11 ships with .NET 4.8. If you are seeing this, you are likely on an older machine, a stripped Windows image, or a system where something removed it. Note also that Windows 10 versions 1507 and 1511 cannot install the .NET SimHub's web server needs at all — on those, a newer Windows is the only route.
It used to start and now it does not
If nothing about your .NET changed, suspect a plugin. This is the official troubleshooting page's own first recommendation, and it is right.
- Disable all third-party plugins. If SimHub starts, re-enable them one at a time until it stops again.
- Think about what changed. A plugin you installed last week, a plugin that auto-updated, or a SimHub update that a plugin was not built against.
- Check the plugin's repository. An abandoned project is a strong candidate — a plugin compiled against an older SimHub can fail on a new one.
Plugins run inside SimHub's own process, which is why a fault in one is indistinguishable from a fault in SimHub until you remove it from the picture. The plugin directory has more on this.
It vanished entirely
If SimHub.exe is missing rather than failing, your antivirus quarantined it. SimHub reads UDP, TCP and shared memory and uses cryptography, which is the exact behaviour signature heuristic scanners flag.
This is a false positive. Force a Defender definition update — new releases are usually cleared within about 24 hours — then restore the file. The full ladder is on antivirus and SimHub.
The reset ladder
Three repair options, and you should try them in this order because each costs more than the last.
| Step | What it does | What you lose |
|---|---|---|
| 1. Light Reinstall | Replaces program files only | Nothing |
| 2. Local User Settings Reset | Clears %localappdata% | Your licence, plus every setting, profile, dashboard and ShakeIt configuration |
| 3. Full Reset | Everything above, plus the installation | As above |
Step two deletes your licence. Back up %localappdata% first. This catches people who are following troubleshooting advice in good faith, because the step is presented as a repair rather than as a deletion. Copy that folder somewhere before you run it — it takes ten seconds and it is the difference between a fix and an afternoon rebuilding dashboards.
Keep the licence email too. If the file is gone and you have no backup, that email is how you get the licence back.
Less common causes
- A corrupted settings file. This is what step two of the ladder actually fixes. If SimHub starts after a settings reset, that was it — and the cost was everything in that folder, which is why the backup matters.
- Running as administrator when it does not need to be. Elevating SimHub creates files with permissions that later non-elevated runs cannot write. Match SimHub's elevation to the game's, and no higher.
- A second copy already running. Check the system tray and Task Manager before launching again. SimHub can be minimised to the tray, so "it will not start" sometimes means "it is already started".
- Audio software interfering with rendering. A file named
mahimicosd.dll, shipped with some audio suites, has been reported as causing rendering glitches. We have not verified this ourselves and flag it as reported rather than confirmed — but if you have audio enhancement software installed and SimHub renders strangely, it is worth eliminating.
Before you ask for help
If SimHub gets far enough to open, the System Informations page reports your version, .NET version, hardware and detected devices in one place. If it does not open at all, bring:
- Your Windows version and build.
- Whether .NET Framework 4.8 is installed.
- The exact SimHub version — from the installer filename if nothing else.
- Which plugins you have, and whether the problem survives disabling them.
- What changed immediately before it broke. Something almost always did.
Discord is the primary support channel now; forum registration is paused because of spam, though the forum archive remains searchable and is often faster than asking.
Common questions
Why does SimHub hang on "Initializing: CoreData"?
Missing .NET Framework 4.8. There is no error dialog because there is no code path for an incomplete framework — it simply stops at that line. Install .NET 4.8 from Microsoft and restart.
SimHub worked yesterday and won't start today.
Disable third-party plugins first — the official troubleshooting page names them as the leading cause of instability, and a plugin can auto-update or be broken by a SimHub update without you doing anything. If that does not help, try a Light Reinstall before anything more destructive.
Will resetting SimHub delete my dashboards?
The Local User Settings Reset will — it clears %localappdata%, which holds your dashboards, profiles, settings and your licence. A Light Reinstall does not touch any of it. Always try the Light Reinstall first and back up %localappdata% before going further.
I ran a reset and lost my licence. Can I get it back?
Yes — your original licence email is the route back. That is why keeping it matters. Restore from a backup of %localappdata% if you have one; otherwise re-apply the licence from the email.
SimHub.exe has disappeared.
Your antivirus quarantined it as a false positive. SimHub reads UDP, TCP and shared memory and uses cryptography — the exact signature heuristic scanners look for. Force a Defender definition update, which usually clears a new release within 24 hours, then restore the file.
Should I run SimHub as administrator to fix startup problems?
No. Elevate only if the game or its launcher is elevated, because rights have to match for shared-memory reads. Elevating unnecessarily creates files whose permissions later non-elevated runs cannot write, which causes a different problem down the line.
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.