diff --git a/cli/src/__tests__/company-import-export-e2e.test.ts b/cli/src/__tests__/company-import-export-e2e.test.ts
index 82f1f1ca..27334105 100644
--- a/cli/src/__tests__/company-import-export-e2e.test.ts
+++ b/cli/src/__tests__/company-import-export-e2e.test.ts
@@ -63,7 +63,7 @@ async function startTempDatabase() {
     password: "paperclip",
     port,
     persistent: true,
-    initdbFlags: ["--encoding=UTF8", "--locale=C"],
+    initdbFlags: ["--encoding=UTF8", "--locale=C", "--lc-messages=C"],
     onLog: () => {},
     onError: () => {},
   });
diff --git a/cli/src/commands/worktree.ts b/cli/src/commands/worktree.ts
index 877f6bdd..7a2bd127 100644
--- a/cli/src/commands/worktree.ts
+++ b/cli/src/commands/worktree.ts
@@ -756,7 +756,7 @@ async function ensureEmbeddedPostgres(dataDir: string, preferredPort: number): P
     password: "paperclip",
     port,
     persistent: true,
-    initdbFlags: ["--encoding=UTF8", "--locale=C"],
+    initdbFlags: ["--encoding=UTF8", "--locale=C", "--lc-messages=C"],
     onLog: () => {},
     onError: () => {},
   });
diff --git a/package.json b/package.json
index 0f5c23ad..749cc8d0 100644
--- a/package.json
+++ b/package.json
@@ -35,8 +35,8 @@
     "test:release-smoke:headed": "npx playwright test --config tests/release-smoke/playwright.config.ts --headed"
   },
   "devDependencies": {
-    "cross-env": "^10.1.0",
     "@playwright/test": "^1.58.2",
+    "cross-env": "^10.1.0",
     "esbuild": "^0.27.3",
     "typescript": "^5.7.3",
     "vitest": "^3.0.5"
@@ -44,5 +44,10 @@
   "engines": {
     "node": ">=20"
   },
-  "packageManager": "pnpm@9.15.4"
+  "packageManager": "pnpm@9.15.4",
+  "pnpm": {
+    "patchedDependencies": {
+      "embedded-postgres@18.1.0-beta.16": "patches/embedded-postgres@18.1.0-beta.16.patch"
+    }
+  }
 }
diff --git a/packages/db/src/client.test.ts b/packages/db/src/client.test.ts
index 9a86a7b3..752fce15 100644
--- a/packages/db/src/client.test.ts
+++ b/packages/db/src/client.test.ts
@@ -67,7 +67,7 @@ async function createTempDatabase(): Promise<string> {
     password: "paperclip",
     port,
     persistent: true,
-    initdbFlags: ["--encoding=UTF8", "--locale=C"],
+    initdbFlags: ["--encoding=UTF8", "--locale=C", "--lc-messages=C"],
     onLog: () => {},
     onError: () => {},
   });
diff --git a/packages/db/src/migration-runtime.ts b/packages/db/src/migration-runtime.ts
index 3b5921b1..921de612 100644
--- a/packages/db/src/migration-runtime.ts
+++ b/packages/db/src/migration-runtime.ts
@@ -150,7 +150,7 @@ async function ensureEmbeddedPostgresConnection(
     password: "paperclip",
     port: selectedPort,
     persistent: true,
-    initdbFlags: ["--encoding=UTF8", "--locale=C"],
+    initdbFlags: ["--encoding=UTF8", "--locale=C", "--lc-messages=C"],
     onLog: () => {},
     onError: () => {},
   });
diff --git a/patches/embedded-postgres@18.1.0-beta.16.patch b/patches/embedded-postgres@18.1.0-beta.16.patch
new file mode 100644
index 00000000..0f25ff39
--- /dev/null
+++ b/patches/embedded-postgres@18.1.0-beta.16.patch
@@ -0,0 +1,22 @@
+diff --git a/dist/index.js b/dist/index.js
+index ccfe17a82f4879bf20cc345c579a987d9eba5309..dd689f5908f625f49b4785318daea736aa88927f 100644
+--- a/dist/index.js
++++ b/dist/index.js
+@@ -133,7 +133,7 @@ class EmbeddedPostgres {
+                     `--pwfile=${passwordFile}`,
+                     `--lc-messages=${LC_MESSAGES_LOCALE}`,
+                     ...this.options.initdbFlags,
+-                ], Object.assign(Object.assign({}, permissionIds), { env: { LC_MESSAGES: LC_MESSAGES_LOCALE } }));
++                ], Object.assign(Object.assign({}, permissionIds), { env: Object.assign(Object.assign({}, process.env), { LC_MESSAGES: LC_MESSAGES_LOCALE }) }));
+                 // Connect to stderr, as that is where the messages get sent
+                 (_a = process.stdout) === null || _a === void 0 ? void 0 : _a.on('data', (chunk) => {
+                     // Parse the data as a string and log it
+@@ -177,7 +177,7 @@ class EmbeddedPostgres {
+                     '-p',
+                     this.options.port.toString(),
+                     ...this.options.postgresFlags,
+-                ], Object.assign(Object.assign({}, permissionIds), { env: { LC_MESSAGES: LC_MESSAGES_LOCALE } }));
++                ], Object.assign(Object.assign({}, permissionIds), { env: Object.assign(Object.assign({}, process.env), { LC_MESSAGES: LC_MESSAGES_LOCALE }) }));
+                 // Connect to stderr, as that is where the messages get sent
+                 (_a = this.process.stderr) === null || _a === void 0 ? void 0 : _a.on('data', (chunk) => {
+                     // Parse the data as a string and log it
diff --git a/server/src/__tests__/heartbeat-process-recovery.test.ts b/server/src/__tests__/heartbeat-process-recovery.test.ts
index a5742f42..d0e3cc31 100644
--- a/server/src/__tests__/heartbeat-process-recovery.test.ts
+++ b/server/src/__tests__/heartbeat-process-recovery.test.ts
@@ -72,7 +72,7 @@ async function startTempDatabase() {
     password: "paperclip",
     port,
     persistent: true,
-    initdbFlags: ["--encoding=UTF8", "--locale=C"],
+    initdbFlags: ["--encoding=UTF8", "--locale=C", "--lc-messages=C"],
     onLog: () => {},
     onError: () => {},
   });
diff --git a/server/src/__tests__/issues-service.test.ts b/server/src/__tests__/issues-service.test.ts
index 70b99ba8..ba27866f 100644
--- a/server/src/__tests__/issues-service.test.ts
+++ b/server/src/__tests__/issues-service.test.ts
@@ -68,7 +68,7 @@ async function startTempDatabase() {
     password: "paperclip",
     port,
     persistent: true,
-    initdbFlags: ["--encoding=UTF8", "--locale=C"],
+    initdbFlags: ["--encoding=UTF8", "--locale=C", "--lc-messages=C"],
     onLog: () => {},
     onError: () => {},
   });
diff --git a/server/src/__tests__/routines-e2e.test.ts b/server/src/__tests__/routines-e2e.test.ts
index 301f045f..83689724 100644
--- a/server/src/__tests__/routines-e2e.test.ts
+++ b/server/src/__tests__/routines-e2e.test.ts
@@ -130,7 +130,7 @@ async function startTempDatabase() {
     password: "paperclip",
     port,
     persistent: true,
-    initdbFlags: ["--encoding=UTF8", "--locale=C"],
+    initdbFlags: ["--encoding=UTF8", "--locale=C", "--lc-messages=C"],
     onLog: () => {},
     onError: () => {},
   });
diff --git a/server/src/__tests__/routines-service.test.ts b/server/src/__tests__/routines-service.test.ts
index ee2e261e..d5954246 100644
--- a/server/src/__tests__/routines-service.test.ts
+++ b/server/src/__tests__/routines-service.test.ts
@@ -76,7 +76,7 @@ async function startTempDatabase() {
     password: "paperclip",
     port,
     persistent: true,
-    initdbFlags: ["--encoding=UTF8", "--locale=C"],
+    initdbFlags: ["--encoding=UTF8", "--locale=C", "--lc-messages=C"],
     onLog: () => {},
     onError: () => {},
   });
diff --git a/server/src/index.ts b/server/src/index.ts
index eb0964ee..d47d6674 100644
--- a/server/src/index.ts
+++ b/server/src/index.ts
@@ -347,7 +347,7 @@ export async function startServer(): Promise<StartedServer> {
           password: "paperclip",
           port,
           persistent: true,
-          initdbFlags: ["--encoding=UTF8", "--locale=C"],
+          initdbFlags: ["--encoding=UTF8", "--locale=C", "--lc-messages=C"],
           onLog: appendEmbeddedPostgresLog,
           onError: appendEmbeddedPostgresLog,
         });