diff --git a/README.md b/README.md
index 1869115..147789d 100644
--- a/README.md
+++ b/README.md
@@ -1348,7 +1348,7 @@ sh.tempDir(function(err, tmp) {
 });
 ```
 
-#### sh.mkdirp(callback)<a name="mkdirp"></a>
+#### sh.mkdirp(path, callback)<a name="mkdirp"></a>
 
 Recursively creates the directory at the provided path. If the 
 directory already exists, no error is returned. All parents must
diff --git a/src/providers/indexeddb.js b/src/providers/indexeddb.js
index 2658163..4975d60 100644
--- a/src/providers/indexeddb.js
+++ b/src/providers/indexeddb.js
@@ -9,6 +9,7 @@ define(function(require) {
 
   var IDB_RW = require('src/constants').IDB_RW;
   var IDB_RO = require('src/constants').IDB_RO;
+  var Errors = require('src/errors');
 
   function IndexedDBContext(db, mode) {
     var transaction = db.transaction(FILE_STORE_NAME, mode);
@@ -112,7 +113,7 @@ define(function(require) {
       callback(null, firstAccess);
     };
     openRequest.onerror = function onerror(error) {
-      callback(error);
+      callback(new Errors.EINVAL('IndexedDB cannot be accessed. If private browsing is enabled, disable it.'));
     };
   };
   IndexedDB.prototype.getReadOnlyContext = function() {
diff --git a/src/providers/websql.js b/src/providers/websql.js
index 4101de1..c765f8a 100644
--- a/src/providers/websql.js
+++ b/src/providers/websql.js
@@ -5,6 +5,7 @@ define(function(require) {
   var WSQL_SIZE = require('src/constants').WSQL_SIZE;
   var WSQL_DESC = require('src/constants').WSQL_DESC;
   var u8toArray = require('src/shared').u8toArray;
+  var Errors = require('src/errors');
 
   function WebSQLContext(db, isReadOnly) {
     var that = this;
@@ -116,6 +117,9 @@ define(function(require) {
     }
 
     function onError(transaction, error) {
+      if (error.code === 5) {
+        callback(new Errors.EINVAL('WebSQL cannot be accessed. If private browsing is enabled, disable it.'));
+      }
       callback(error);
     }
     function onSuccess(transaction, result) {
diff --git a/src/shell/shell.js b/src/shell/shell.js
index 97f91a1..22f2d01 100644
--- a/src/shell/shell.js
+++ b/src/shell/shell.js
@@ -499,19 +499,32 @@ define(function(require) {
     callback = callback || function(){};
 
     if(!path) {
-      callback(new Errors.EINVAL('missing path argument'));
+      callback(new Errors.EINVAL("Missing path argument"));
       return;
     }
-    else if (path === '/'){
+    else if (path === '/') {
       callback();
       return;
     }
-    function _mkdirp(path, callback){
+    function _mkdirp(path, callback) {
       fs.stat(path, function (err, stat) {
-        //doesn't exist
-        if (err && err.code === 'ENOENT') {
+        if(stat) {
+          if(stat.isDirectory()) {
+            callback();
+            return;
+          }
+          else if (stat.isFile()) {
+            callback(new Errors.ENOTDIR());
+            return;
+          }
+        }
+        else if (err && err.code !== 'ENOENT') {
+          callback(err);
+          return;
+        }
+        else {
           var parent = Path.dirname(path);
-          if(parent === '/'){ //parent is root
+          if(parent === '/') {
             fs.mkdir(path, function (err) {
               if (err && err.code != 'EEXIST') {
                 callback(err);
@@ -521,10 +534,10 @@ define(function(require) {
               return;
             });
           }
-          else { //parent is not root, make parent first
+          else {
             _mkdirp(parent, function (err) {
               if (err) return callback(err);
-              fs.mkdir(path, function (err) { //then make dir
+              fs.mkdir(path, function (err) {
                 if (err && err.code != 'EEXIST') {
                   callback(err);
                   return;
@@ -535,21 +548,7 @@ define(function(require) {
             });
           }
         }
-        //other error
-        else if (err){
-          callback(err);
-          return;
-        }
-        //already exists
-        else if (stat.type === 'DIRECTORY') {
-          callback();
-          return;
-        }
-        //not a directory
-        else if (stat.type === 'FILE') {
-          callback(new Errors.ENOTDIR());
-          return;
-        }
+
       });
     }