---
title: ROB RUN Errors and Fixes: Shaders, E-0403, Crashes, FPS
description: Fixes players report for ROB RUN launch problems: stuck on preparing shaders, login errors E-0403 and E-0405, loading-screen crashes, voice chat and the B-coin button.
url: https://robrunwiki.org/game/errors-and-fixes/
---

file: what broke

# ROB RUN errors and fixes
**Short answer:** first check whether the [servers are up](https://robrunwiki.org/game/servers-and-wipes/#maintenance). Then **verify the game files** in Steam (Library, right-click ROB RUN, Properties, Installed Files, Verify integrity): it fixed E-0405 and loading-screen crashes for players. A crash a few minutes in usually means your CPU lacks [AVX2](https://robrunwiki.org/game/system-requirements/#avx2).

None of these fixes come from Kefir; they are what players report worked in launch week. Each section says how many people saw it.

## Stuck on "preparing shaders"
The loading bar freezes on the shader step. Players in four separate threads report it, often after quitting a long load and relaunching.

- Give the first launch time: shaders compile once.

- Close the game fully and verify the game files.

- One player got past it with a VPN, which points to a connection step rather than the GPU.

## Login error E-0403 or E-0405
E-0403 shows as `EosAuthorizationError ... Login result NoConnection`: the game cannot reach Epic Online Services to log you in.

- **Verify the game files.** This solved E-0405 for the player who reported it.

- **Turn off any VPN or proxy,** then reset Windows' proxy setting: open Command Prompt as administrator and run `netsh winhttp reset proxy`.

- One player fixed E-0403 by reinstalling the Epic Games Launcher.

## Crashes on the loading screen or at launch
Players reporting "Failed to load il2cpp" or crashes during loading fixed it by verifying the files. If that fails, a launch-week fix video adds: run the game's exe as administrator, disable fullscreen optimisations in its compatibility settings, turn off the Steam overlay, clear Steam's download cache and update Windows and GPU drivers. A crash about five minutes in after an AVX2 warning is the [AVX2 problem](https://robrunwiki.org/game/system-requirements/#avx2); none of these steps fix that.

## Low FPS and stutter
Several threads report freezes and FPS drops, worse in crowded spots. Check your PC against the [requirements](https://robrunwiki.org/game/system-requirements/#specs): the minimum is 12 GB RAM, more than most games ask. Kefir has said it is fixing technical issues found in the playtest but has posted no performance patch yet.

## Voice chat does not work
Two players suggest a VPN, or Cloudflare WARP set to route traffic and DNS, for silent voice chat, which points to a regional network block. Elsewhere, check Windows' microphone permissions and the game's audio settings.

## B-coin or battle pass button does nothing
Three players report the B-coin purchase button staying inactive with funds in their Steam wallet. No fix has been found; it looks like a bug on Kefir's side.

## Where to report a ROB RUN bug
The Steam discussions for ROB RUN and Kefir's official Discord, linked from the game's Steam news posts. Include your error code, CPU and GPU.

## Watch the fix steps

- [Fix ROB RUN crashing, not launching & crash to desktop](https://www.youtube.com/watch?v=CiCsWIsLeNo) Master Fixing · early access build jump to [00:00](https://www.youtube.com/watch?v=CiCsWIsLeNo&t=0s), [00:40](https://www.youtube.com/watch?v=CiCsWIsLeNo&t=40s), [01:00](https://www.youtube.com/watch?v=CiCsWIsLeNo&t=60s)

Checked 2026-11-06 against the Early Access build (launched 4 November 2026). [How this wiki checks facts](https://robrunwiki.org/about/#how).

## More Game Info guides

- [Servers & wipes When new ROB RUN servers open in the EU and East US, how the 7-day wipe works, what a wipe takes, how to change server, party size, solo play and maintenance. open the file →](https://robrunwiki.org/game/servers-and-wipes/)

- [System requirements ROB RUN minimum and recommended PC specs, why it crashes on CPUs without AVX2, whether it runs on Linux, Steam Deck or GeForce Now, and controller support. open the file →](https://robrunwiki.org/game/system-requirements/)

- [Release, price & platforms When ROB RUN came out, whether it is free or pay to win, if it is on PS5, Xbox or mobile, who makes it, supported languages and how the playtest worked. open the file →](https://robrunwiki.org/game/release-price-platforms/)