diff --git a/packages/node_modules/@node-red/registry/lib/externalModules.js b/packages/node_modules/@node-red/registry/lib/externalModules.js
index b61392d9b..b76f748a4 100644
--- a/packages/node_modules/@node-red/registry/lib/externalModules.js
+++ b/packages/node_modules/@node-red/registry/lib/externalModules.js
@@ -242,63 +242,68 @@ async function ensureModuleDir() {
     }
 }
 
+let installLock = Promise.resolve()
 async function installModule(moduleDetails) {
-    let installSpec = moduleDetails.module;
-    if (!registryUtil.checkModuleAllowed( moduleDetails.module, moduleDetails.version,installAllowList,installDenyList)) {
-        const e = new Error("Install not allowed");
-        e.code = "install_not_allowed";
-        throw e;
-    }
-    if (moduleDetails.version) {
-        installSpec = installSpec+"@"+moduleDetails.version;
-    }
-    log.info(log._("server.install.installing",{name: moduleDetails.module,version: moduleDetails.version||"latest"}));
-    const installDir = getInstallDir();
-
-    await ensureModuleDir();
-
-    let triggerPayload = {
-        "module": moduleDetails.module,
-        "version": moduleDetails.version,
-        "dir": installDir,
-        "args": ["--production","--engine-strict"]
-    }
-    return hooks.trigger("preInstall", triggerPayload).then((result) => {
-        // preInstall passed
-        // - run install
-        if (result !== false) {
-            let extraArgs = triggerPayload.args || [];
-            let args = ['install', ...extraArgs, installSpec]
-            log.trace(NPM_COMMAND + JSON.stringify(args));
-            return exec.run(NPM_COMMAND, args, { cwd: installDir },true)
-        } else {
-            log.trace("skipping npm install");
-        }
-    }).then(() => {
-        return hooks.trigger("postInstall", triggerPayload)
-    }).then(() => {
-        log.info(log._("server.install.installed", { name: installSpec }));
-        const runtimeInstalledModules = settings.get("modules") || {};
-        runtimeInstalledModules[moduleDetails.module] = moduleDetails;
-        settings.set("modules",runtimeInstalledModules)
-    }).catch(result => {
-        var output = result.stderr || result.toString();
-        var e;
-        if (/E404/.test(output) || /ETARGET/.test(output)) {
-            log.error(log._("server.install.install-failed-not-found",{name:installSpec}));
-            e = new Error("Module not found");
-            e.code = 404;
-            throw e;
-        } else {
-            log.error(log._("server.install.install-failed-long",{name:installSpec}));
-            log.error("------------------------------------------");
-            log.error(output);
-            log.error("------------------------------------------");
-            e = new Error(log._("server.install.install-failed"));
-            e.code = "unexpected_error";
+    const result = installLock.then(async () => {
+        let installSpec = moduleDetails.module;
+        if (!registryUtil.checkModuleAllowed( moduleDetails.module, moduleDetails.version,installAllowList,installDenyList)) {
+            const e = new Error("Install not allowed");
+            e.code = "install_not_allowed";
             throw e;
         }
+        if (moduleDetails.version) {
+            installSpec = installSpec+"@"+moduleDetails.version;
+        }
+        log.info(log._("server.install.installing",{name: moduleDetails.module,version: moduleDetails.version||"latest"}));
+        const installDir = getInstallDir();
+
+        await ensureModuleDir();
+
+        let triggerPayload = {
+            "module": moduleDetails.module,
+            "version": moduleDetails.version,
+            "dir": installDir,
+            "args": ["--production","--engine-strict"]
+        }
+        return hooks.trigger("preInstall", triggerPayload).then((result) => {
+            // preInstall passed
+            // - run install
+            if (result !== false) {
+                let extraArgs = triggerPayload.args || [];
+                let args = ['install', ...extraArgs, installSpec]
+                log.trace(NPM_COMMAND + JSON.stringify(args));
+                return exec.run(NPM_COMMAND, args, { cwd: installDir },true)
+            } else {
+                log.trace("skipping npm install");
+            }
+        }).then(() => {
+            return hooks.trigger("postInstall", triggerPayload)
+        }).then(() => {
+            log.info(log._("server.install.installed", { name: installSpec }));
+            const runtimeInstalledModules = settings.get("modules") || {};
+            runtimeInstalledModules[moduleDetails.module] = moduleDetails;
+            settings.set("modules",runtimeInstalledModules)
+        }).catch(result => {
+            var output = result.stderr || result.toString();
+            var e;
+            if (/E404/.test(output) || /ETARGET/.test(output)) {
+                log.error(log._("server.install.install-failed-not-found",{name:installSpec}));
+                e = new Error("Module not found");
+                e.code = 404;
+                throw e;
+            } else {
+                log.error(log._("server.install.install-failed-long",{name:installSpec}));
+                log.error("------------------------------------------");
+                log.error(output);
+                log.error("------------------------------------------");
+                e = new Error(log._("server.install.install-failed"));
+                e.code = "unexpected_error";
+                throw e;
+            }
+        })
     })
+    installLock = result.catch(() => {})
+    return result
 }
 
 module.exports = {