diff --git a/README.md b/README.md
index 51f67cc8d0..46da063d41 100644
--- a/README.md
+++ b/README.md
@@ -113,6 +113,19 @@ Controls the maximum number of HTTP requests that can be done simultaneously.
 
 Controls the number of child processes run parallely to build node modules.
 
+#### lock
+
+* Default: **true**
+* Type: **Boolean**
+
+Dangerous! If false, the store is not locked. It means that several installations using the same
+store can run simultaneously.
+
+Can be passed in via a CLI option. `--no-lock` to set it to false. E.g.: `pnpm install --no-lock`.
+
+> If you experience issues similar to the ones described in [#594](https://github.com/pnpm/pnpm/issues/594), use this option to disable locking.
+> In the meanwhile, we'll try to find a solution that will make locking work for everyone.
+
 ## Benchmark
 
 pnpm is usually 10 times faster than npm and 30% faster than yarn. See [this](https://github.com/zkochan/node-package-manager-benchmark)
diff --git a/src/api/extendOptions.ts b/src/api/extendOptions.ts
index 3377a5cb0a..db8d3277ce 100644
--- a/src/api/extendOptions.ts
+++ b/src/api/extendOptions.ts
@@ -29,6 +29,7 @@ const defaults = (opts: PnpmOptions) => {
     networkConcurrency: 16,
     fetchingConcurrency: 16,
     lockStaleDuration: 60 * 1000, // 1 minute
+    lock: true,
     childConcurrency: 5,
     offline: false,
     registry: 'https://registry.npmjs.org/',
@@ -52,6 +53,9 @@ export default (opts?: PnpmOptions): StrictPnpmOptions => {
   if (extendedOpts.force) {
     logger.warn('using --force I sure hope you know what you are doing')
   }
+  if (extendedOpts.lock === false) {
+    logger.warn('using --no-lock I sure hope you know what you are doing')
+  }
   if (extendedOpts.localRegistry !== DEFAULT_LOCAL_REGISTRY) {
     extendedOpts.localRegistry = expandTilde(extendedOpts.localRegistry, extendedOpts.prefix)
   }
diff --git a/src/api/install.ts b/src/api/install.ts
index 7110ac1287..7e85ca17d4 100644
--- a/src/api/install.ts
+++ b/src/api/install.ts
@@ -61,25 +61,27 @@ export async function install (maybeOpts?: PnpmOptions) {
 
   const optionalDeps = R.keys(ctx.pkg.optionalDependencies)
 
-  return lock(
-    ctx.storePath,
-    async () => {
-      const scripts = !opts.ignoreScripts && ctx.pkg && ctx.pkg.scripts || {}
-      if (scripts['preinstall']) {
-        npmRun('preinstall', ctx.root, opts.userAgent)
-      }
+  if (opts.lock === false) {
+    return run()
+  }
 
-      await installInContext(installType, specs, optionalDeps, [], ctx, installCtx, opts)
+  return lock(ctx.storePath, run, {stale: opts.lockStaleDuration})
 
-      if (scripts['postinstall']) {
-        npmRun('postinstall', ctx.root, opts.userAgent)
-      }
-      if (scripts['prepublish']) {
-        npmRun('prepublish', ctx.root, opts.userAgent)
-      }
-    },
-    {stale: opts.lockStaleDuration}
-  )
+  async function run () {
+    const scripts = !opts.ignoreScripts && ctx.pkg && ctx.pkg.scripts || {}
+    if (scripts['preinstall']) {
+      npmRun('preinstall', ctx.root, opts.userAgent)
+    }
+
+    await installInContext(installType, specs, optionalDeps, [], ctx, installCtx, opts)
+
+    if (scripts['postinstall']) {
+      npmRun('postinstall', ctx.root, opts.userAgent)
+    }
+    if (scripts['prepublish']) {
+      npmRun('prepublish', ctx.root, opts.userAgent)
+    }
+  }
 }
 
 function specsToInstallFromPackage(
@@ -131,18 +133,22 @@ export async function installPkgs (fuzzyDeps: string[] | Dependencies, maybeOpts
     ? packagesToInstall.map(spec => spec.name)
     : []
 
-  return lock(
-    ctx.storePath,
-    () => installInContext(
+  if (opts.lock === false) {
+    return run()
+  }
+
+  return lock(ctx.storePath, run, {stale: opts.lockStaleDuration})
+
+  function run () {
+    return installInContext(
       installType,
       packagesToInstall,
       optionalDependencies,
       packagesToInstall.map(spec => spec.name),
       ctx,
       installCtx,
-      opts),
-    {stale: opts.lockStaleDuration}
-  )
+      opts)
+  }
 }
 
 function argsToSpecs (args: string[], defaultTag: string, where: string): PackageSpec[] {
diff --git a/src/api/prune.ts b/src/api/prune.ts
index 0d47ee0c24..63d8ada3cb 100644
--- a/src/api/prune.ts
+++ b/src/api/prune.ts
@@ -19,7 +19,13 @@ export async function prune(maybeOpts?: PnpmOptions): Promise<void> {
 
   const ctx = await getContext(opts)
 
-  return lock(ctx.storePath, async function () {
+  if (opts.lock === false) {
+    return run()
+  }
+
+  return lock(ctx.storePath, run, {stale: opts.lockStaleDuration})
+
+  async function run () {
     if (!ctx.pkg) {
       throw new Error('No package.json found - cannot prune')
     }
@@ -37,8 +43,7 @@ export async function prune(maybeOpts?: PnpmOptions): Promise<void> {
     const prunedShr = pruneShrinkwrap(newShr)
 
     await removeOrphanPkgs(ctx.privateShrinkwrap, prunedShr, ctx.root, ctx.storePath)
-  },
-  {stale: opts.lockStaleDuration})
+  }
 }
 
 async function getExtraneousPkgs (pkg: Package, root: string, production: boolean) {
diff --git a/src/api/uninstall.ts b/src/api/uninstall.ts
index 0a9d3a1f50..0f241fd320 100644
--- a/src/api/uninstall.ts
+++ b/src/api/uninstall.ts
@@ -32,11 +32,16 @@ export default async function uninstallCmd (pkgsToUninstall: string[], maybeOpts
   }
 
   const pkg = ctx.pkg
-  return lock(
-    ctx.storePath,
-    () => uninstallInContext(pkgsToUninstall, pkg, ctx, opts),
-    {stale: opts.lockStaleDuration}
-  )
+
+  if (opts.lock === false) {
+    return run()
+  }
+
+  return lock(ctx.storePath, run, {stale: opts.lockStaleDuration})
+
+  function run () {
+    return uninstallInContext(pkgsToUninstall, pkg, ctx, opts)
+  }
 }
 
 export async function uninstallInContext (pkgsToUninstall: string[], pkg: Package, ctx: PnpmContext, opts: StrictPnpmOptions) {
diff --git a/src/bin/pnpm.ts b/src/bin/pnpm.ts
index fd5ee79280..7f90035139 100755
--- a/src/bin/pnpm.ts
+++ b/src/bin/pnpm.ts
@@ -59,6 +59,7 @@ async function run (argv: string[]) {
     'network-concurrency': Number,
     'fetching-concurrency': Number,
     'lock-stale-duration': Number,
+    'lock': Boolean,
     'child-concurrency': Number,
     'offline': Boolean,
     'reporter': String,
diff --git a/src/types.ts b/src/types.ts
index 81d5beaabe..0b455578e5 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -46,6 +46,7 @@ export type PnpmOptions = {
   networkConcurrency?: number,
   fetchingConcurrency?: number,
   lockStaleDuration?: number,
+  lock?: boolean,
   childConcurrency?: number,
   repeatInstallDepth?: number,
 
@@ -98,6 +99,7 @@ export type StrictPnpmOptions = {
   networkConcurrency: number,
   fetchingConcurrency: number,
   lockStaleDuration: number,
+  lock: boolean,
   childConcurrency: number,
   repeatInstallDepth: number,