diff --git a/lib/manager/npm/post-update/lerna.ts b/lib/manager/npm/post-update/lerna.ts
index dc275c9c00a663323dcd3ca2d33a7a93b3beef67..799cb482a4697617abaf78ab3be89c219170e178 100644
--- a/lib/manager/npm/post-update/lerna.ts
+++ b/lib/manager/npm/post-update/lerna.ts
@@ -43,8 +43,7 @@ export async function generateLockFiles(
         params = '--package-lock-only --no-audit';
       }
     } else {
-      params =
-        '--ignore-scripts --ignore-engines --ignore-platform --mutex network:31879';
+      params = '--ignore-scripts --ignore-engines --ignore-platform';
     }
 
     // // istanbul ignore if
diff --git a/lib/manager/npm/post-update/yarn.ts b/lib/manager/npm/post-update/yarn.ts
index 6d70c31e0ee7209aba338877e50080835761b4b1..10de4aef28ea9047dbd2e31419b39d2f25e80345 100644
--- a/lib/manager/npm/post-update/yarn.ts
+++ b/lib/manager/npm/post-update/yarn.ts
@@ -103,9 +103,6 @@ export async function generateLockFile(
     }
     cmdExtras += ' --ignore-engines';
     cmdExtras += ' --ignore-platform';
-    cmdExtras += process.env.YARN_MUTEX_FILE
-      ? ` --mutex file:${process.env.YARN_MUTEX_FILE}`
-      : ' --mutex network:31879';
     const installCmd = cmd + ' install' + cmdExtras;
     // TODO: Switch to native util.promisify once using only node 8
     await exec(installCmd, {
diff --git a/lib/workers/branch/lock-files/__snapshots__/lerna.spec.ts.snap b/lib/workers/branch/lock-files/__snapshots__/lerna.spec.ts.snap
index 317a862918b9a09d2534a6833a15dc743ba78f0c..4c64806349f7a985ff4ce15fde253e817d47f6a9 100644
--- a/lib/workers/branch/lock-files/__snapshots__/lerna.spec.ts.snap
+++ b/lib/workers/branch/lock-files/__snapshots__/lerna.spec.ts.snap
@@ -81,7 +81,7 @@ Array [
 exports[`generateLockFiles() generates yarn.lock files 1`] = `
 Array [
   Object {
-    "cmd": "yarn install --ignore-scripts --ignore-engines --ignore-platform --mutex network:31879",
+    "cmd": "yarn install --ignore-scripts --ignore-engines --ignore-platform",
     "options": Object {
       "cwd": "some-dir",
       "encoding": "utf-8",
@@ -98,7 +98,7 @@ Array [
     },
   },
   Object {
-    "cmd": "npx lerna@2.0.0 bootstrap --no-ci -- --ignore-scripts --ignore-engines --ignore-platform --mutex network:31879",
+    "cmd": "npx lerna@2.0.0 bootstrap --no-ci -- --ignore-scripts --ignore-engines --ignore-platform",
     "options": Object {
       "cwd": "some-dir",
       "encoding": "utf-8",
diff --git a/lib/workers/branch/lock-files/__snapshots__/yarn.spec.ts.snap b/lib/workers/branch/lock-files/__snapshots__/yarn.spec.ts.snap
index 8c49d11c16386c4470a16e498f8d4daae245efd5..5223d1c0b9b756d2f39721ec4357945713573ea1 100644
--- a/lib/workers/branch/lock-files/__snapshots__/yarn.spec.ts.snap
+++ b/lib/workers/branch/lock-files/__snapshots__/yarn.spec.ts.snap
@@ -20,7 +20,7 @@ Array [
     },
   },
   Object {
-    "cmd": "<yarn> install --ignore-scripts --ignore-engines --ignore-platform --mutex network:31879",
+    "cmd": "<yarn> install --ignore-scripts --ignore-engines --ignore-platform",
     "options": Object {
       "cwd": "some-dir",
       "encoding": "utf-8",
@@ -59,7 +59,7 @@ Array [
     },
   },
   Object {
-    "cmd": "<yarn> install --ignore-scripts --ignore-engines --ignore-platform --mutex network:31879",
+    "cmd": "<yarn> install --ignore-scripts --ignore-engines --ignore-platform",
     "options": Object {
       "cwd": "some-dir",
       "encoding": "utf-8",
@@ -76,7 +76,7 @@ Array [
     },
   },
   Object {
-    "cmd": "<yarn> upgrade some-dep --ignore-scripts --ignore-engines --ignore-platform --mutex network:31879",
+    "cmd": "<yarn> upgrade some-dep --ignore-scripts --ignore-engines --ignore-platform",
     "options": Object {
       "cwd": "some-dir",
       "encoding": "utf-8",
@@ -115,7 +115,7 @@ Array [
     },
   },
   Object {
-    "cmd": "<yarn> install --ignore-engines --ignore-platform --mutex network:31879",
+    "cmd": "<yarn> install --ignore-engines --ignore-platform",
     "options": Object {
       "cwd": "some-dir",
       "encoding": "utf-8",
@@ -133,7 +133,7 @@ Array [
     },
   },
   Object {
-    "cmd": "<yarn> upgrade some-dep --ignore-engines --ignore-platform --mutex network:31879",
+    "cmd": "<yarn> upgrade some-dep --ignore-engines --ignore-platform",
     "options": Object {
       "cwd": "some-dir",
       "encoding": "utf-8",
@@ -172,7 +172,7 @@ Array [
     },
   },
   Object {
-    "cmd": "<yarn> install --ignore-scripts --ignore-engines --ignore-platform --mutex network:31879",
+    "cmd": "<yarn> install --ignore-scripts --ignore-engines --ignore-platform",
     "options": Object {
       "cwd": "some-dir",
       "encoding": "utf-8",
@@ -211,7 +211,7 @@ Array [
     },
   },
   Object {
-    "cmd": "<yarn> install --ignore-scripts --ignore-engines --ignore-platform --mutex network:31879",
+    "cmd": "<yarn> install --ignore-scripts --ignore-engines --ignore-platform",
     "options": Object {
       "cwd": "some-dir",
       "encoding": "utf-8",
@@ -250,7 +250,7 @@ Array [
     },
   },
   Object {
-    "cmd": "<yarn> install --ignore-engines --ignore-platform --mutex network:31879",
+    "cmd": "<yarn> install --ignore-engines --ignore-platform",
     "options": Object {
       "cwd": "some-dir",
       "encoding": "utf-8",
@@ -290,7 +290,7 @@ Array [
     },
   },
   Object {
-    "cmd": "<yarn> install --ignore-scripts --ignore-engines --ignore-platform --mutex network:31879",
+    "cmd": "<yarn> install --ignore-scripts --ignore-engines --ignore-platform",
     "options": Object {
       "cwd": "some-dir",
       "encoding": "utf-8",
@@ -363,7 +363,7 @@ Array [
     },
   },
   Object {
-    "cmd": "<yarn> install --ignore-engines --ignore-platform --mutex network:31879",
+    "cmd": "<yarn> install --ignore-engines --ignore-platform",
     "options": Object {
       "cwd": "some-dir",
       "encoding": "utf-8",
@@ -403,7 +403,7 @@ Array [
     },
   },
   Object {
-    "cmd": "<yarn> install --ignore-scripts --ignore-engines --ignore-platform --mutex file:/tmp/yarn.mutext",
+    "cmd": "<yarn> install --ignore-scripts --ignore-engines --ignore-platform",
     "options": Object {
       "cwd": "some-dir",
       "encoding": "utf-8",
@@ -420,7 +420,7 @@ Array [
     },
   },
   Object {
-    "cmd": "<yarn> upgrade some-dep --ignore-scripts --ignore-engines --ignore-platform --mutex file:/tmp/yarn.mutext",
+    "cmd": "<yarn> upgrade some-dep --ignore-scripts --ignore-engines --ignore-platform",
     "options": Object {
       "cwd": "some-dir",
       "encoding": "utf-8",
@@ -459,7 +459,7 @@ Array [
     },
   },
   Object {
-    "cmd": "<yarn> install --ignore-engines --ignore-platform --mutex file:/tmp/yarn.mutext",
+    "cmd": "<yarn> install --ignore-engines --ignore-platform",
     "options": Object {
       "cwd": "some-dir",
       "encoding": "utf-8",
@@ -477,7 +477,7 @@ Array [
     },
   },
   Object {
-    "cmd": "<yarn> upgrade some-dep --ignore-engines --ignore-platform --mutex file:/tmp/yarn.mutext",
+    "cmd": "<yarn> upgrade some-dep --ignore-engines --ignore-platform",
     "options": Object {
       "cwd": "some-dir",
       "encoding": "utf-8",
@@ -516,7 +516,7 @@ Array [
     },
   },
   Object {
-    "cmd": "yarn install --ignore-scripts --ignore-engines --ignore-platform --mutex network:31879",
+    "cmd": "yarn install --ignore-scripts --ignore-engines --ignore-platform",
     "options": Object {
       "cwd": "some-dir",
       "encoding": "utf-8",