diff --git a/backend/windmill-worker/src/duckdb_executor.rs b/backend/windmill-worker/src/duckdb_executor.rs
index d3bd976f21..b8c850a2f4 100644
--- a/backend/windmill-worker/src/duckdb_executor.rs
+++ b/backend/windmill-worker/src/duckdb_executor.rs
@@ -2969,7 +2969,7 @@ mod tests {
         assert!(
             attach.starts_with(&format!(
                 "ATTACH 'sslmode=verify-full sslrootcert=''{}''",
-                root
+                root.replace('\\', "\\\\")
             )),
             "{attach}"
         );
diff --git a/cli/test/preview.test.ts b/cli/test/preview.test.ts
index ffa900c8f7..b0b00a2c7e 100644
--- a/cli/test/preview.test.ts
+++ b/cli/test/preview.test.ts
@@ -455,6 +455,12 @@ schema:
 // SCRIPT WITH MODULES PREVIEW TESTS
 // =============================================================================
 
+// Pinned: a release commit runs these tests while the same release publishes a new
+// windmill-client, and the worker resolving that version before npm serves it fails the job.
+// These are the only CLI tests running task/taskScript/workflow on a real client: bump the pin
+// to a published release whenever the WAC client surface changes.
+const WINDMILL_CLIENT = "windmill-client@1.819.0";
+
 test("script preview: script with modules (taskScript pattern)", async () => {
   await withTestBackend(async (backend, tempDir) => {
     await createWmillConfig(tempDir, { defaultTs: "bun" });
@@ -463,7 +469,7 @@ test("script preview: script with modules (taskScript pattern)", async () => {
     await createScript(
       tempDir,
       "f/test/wac_script.ts",
-      `import { task, taskScript, workflow } from "windmill-client";
+      `import { task, taskScript, workflow } from "${WINDMILL_CLIENT}";
 
 const helper = taskScript("./helper.ts");
 
@@ -512,7 +518,7 @@ test("script preview: script with modules (folder layout)", async () => {
     // Entry point script
     await writeFile(
       `${modDir}/script.ts`,
-      `import { task, taskScript, workflow } from "windmill-client";
+      `import { task, taskScript, workflow } from "${WINDMILL_CLIENT}";
 
 const helper = taskScript("./helper.ts");
 
diff --git a/cli/test/raw_app_sync.test.ts b/cli/test/raw_app_sync.test.ts
index 315b274d80..33f1d3f6a6 100644
--- a/cli/test/raw_app_sync.test.ts
+++ b/cli/test/raw_app_sync.test.ts
@@ -61,8 +61,7 @@ root.render(<App/>);
 const PACKAGE_JSON = `{
     "dependencies": {
         "react": "19.0.0",
-        "react-dom": "19.0.0",
-        "windmill-client": "^1"
+        "react-dom": "19.0.0"
     },
     "devDependencies": {
         "@types/react-dom": "^19.0.0",