dotnet/runtime · critical · Error

Mismatched git hashes between loader and runtime. Loader

Error message

Mismatched git hashes between loader and runtime. Loader: ${runtimeApi.runtimeBuildInfo.gitHash}, BrowserUtils: ${GitHash}

What it means

The BrowserUtils module (System.Native.Browser/utils) embeds its own git hash via `consts:gitHash`. During initialization it asserts that hash equals runtimeApi.runtimeBuildInfo.gitHash from the loader. A mismatch means the utils support bundle and the runtime/loader were built from different commits.

Solutions

1. Redeploy the full set of dotnet support JS + wasm from one build so BrowserUtils and the loader agree on the hash.
2. Clear caches (browser, CDN, service worker) that could serve a stale utils bundle.
3. Clean and rebuild the whole solution to ensure a single hash is stamped.
4. Audit the wwwroot/_framework directory to confirm no leftover files from a previous SDK version.

Example fix

// before: utils bundle cached from old deploy

// after: hard reload / cache-bust _framework/*
// then verify both report the same hash in the diagnostics output

import GitHash from "consts:gitHash";

function assertUtilsHashMatches(runtimeApi: any) {
  const loader = runtimeApi?.runtimeBuildInfo?.gitHash;
  if (loader && loader !== GitHash) {
    throw new Error(`Utils build mismatch: loader=${loader}, utils=${GitHash}`);
  }
}

null

null

When it happens

Trigger: Loading a BrowserUtils JS bundle whose baked GitHash differs from the loader's runtimeBuildInfo.gitHash; both are non-empty.

Common situations: Same class of deployment drift as the other git-hash checks: mixed SDK/workload versions in wwwroot, stale CDN/browser cache, partial publish, dev rebuild of only the runtime project.

Related errors

• Mismatched git hashes between loader and runtime. Loader
• Mismatched git hashes between loader and runtime. Loader
• Mismatched git hashes between loader and runtime. Loader
• Mismatched git hashes between loader and runtime. Loader
• Unsupported Webcil version

AI-assisted analysis of dotnet/runtime@60108ba66e (2026-08-10). Data as JSON: /api/errors/5e239455083c0aad. Report an issue: GitHub.

Appendix: source

Thrown at src/native/libs/System.Native.Browser/utils/index.ts:31

    zeroRegion,
    arrayBufferNeedsCopy,
    viewOrCopy,
} from "./memory";
import { stringsInit, stringToUTF16, stringToUTF16Ptr, stringToUTF8, stringToUTF8Ptr, utf16ToString, utf8ToStringRelaxed } from "./strings";
import { abortPosix, getExitStatus } from "./host";
import { dotnetUpdateInternals, dotnetUpdateInternalsSubscriber } from "../utils/cross-module";
import { initPolyfills } from "../utils/polyfills";
import { registerRuntime } from "./runtime-list";
import { registerCDAC } from "./cdac";
import { abortBackgroundTimers, runBackgroundTimers } from "./scheduling";

export function dotnetInitializeModule(internals: InternalExchange): void {
    if (!Array.isArray(internals)) throw new Error("Expected internals to be an array");
    const runtimeApi = internals[InternalExchangeIndex.RuntimeAPI];
    if (typeof runtimeApi !== "object") throw new Error("Expected internals to have RuntimeAPI");

    if (runtimeApi.runtimeBuildInfo.gitHash && runtimeApi.runtimeBuildInfo.gitHash !== GitHash) {
        throw new Error(`Mismatched git hashes between loader and runtime. Loader: ${runtimeApi.runtimeBuildInfo.gitHash}, BrowserUtils: ${GitHash}`);
    }

    initPolyfills();
    stringsInit();
    registerRuntime(runtimeApi);
    registerCDAC(runtimeApi);

    if (!Array.isArray(internals)) throw new Error("Expected internals to be an array");
    const runtimeApiLocal: Partial<RuntimeAPI> = {
        setHeapB32, setHeapB8, setHeapU8, setHeapU16, setHeapU32, setHeapI8, setHeapI16, setHeapI32, setHeapI52, setHeapU52, setHeapI64Big, setHeapF32, setHeapF64,
        getHeapB32, getHeapB8, getHeapU8, getHeapU16, getHeapU32, getHeapI8, getHeapI16, getHeapI32, getHeapI52, getHeapU52, getHeapI64Big, getHeapF32, getHeapF64,
        localHeapViewI8, localHeapViewI16, localHeapViewI32, localHeapViewI64Big, localHeapViewU8, localHeapViewU16, localHeapViewU32, localHeapViewF32, localHeapViewF64,
    };
    Object.assign(runtimeApi, runtimeApiLocal);

    internals[InternalExchangeIndex.BrowserUtilsExportsTable] = browserUtilsExportsToTable({
        utf16ToString,
        stringToUTF16,

View on GitHub (pinned to 60108ba66e)