diff --git a/apps/files_external/controller/storagescontroller.php b/apps/files_external/controller/storagescontroller.php
index 64b989f0c7..b09774ef51 100644
--- a/apps/files_external/controller/storagescontroller.php
+++ b/apps/files_external/controller/storagescontroller.php
@@ -25,6 +25,7 @@ namespace OCA\Files_External\Controller;
 
 
 use \OCP\IConfig;
+use OCP\IUser;
 use \OCP\IUserSession;
 use \OCP\IRequest;
 use \OCP\IL10N;
@@ -114,6 +115,7 @@ abstract class StoragesController extends Controller {
 				$priority
 			);
 		} catch (\InvalidArgumentException $e) {
+			\OC::$server->getLogger()->logException($e);
 			return new DataResponse(
 				[
 					'message' => (string)$this->l10n->t('Invalid backend or authentication mechanism class')
diff --git a/apps/files_external/controller/usercredentialscontroller.php b/apps/files_external/controller/usercredentialscontroller.php
index bc514cba08..5153189d9c 100644
--- a/apps/files_external/controller/usercredentialscontroller.php
+++ b/apps/files_external/controller/usercredentialscontroller.php
@@ -21,12 +21,19 @@
 
 namespace OCA\Files_External\Controller;
 
+use OCA\Calendar\Sabre\Backend;
+use OCA\Files_External\Lib\Auth\AuthMechanism;
 use OCA\Files_External\Lib\Auth\Password\UserProvided;
+use OCA\Files_external\Lib\StorageConfig;
+use OCA\Files_External\Service\UserGlobalStoragesService;
 use OCP\AppFramework\Controller;
+use OCP\AppFramework\Http;
+use OCP\AppFramework\Http\DataResponse;
+use OCP\IL10N;
 use OCP\IRequest;
 use OCP\IUserSession;
 
-class UserCredentialsController extends Controller {
+class UserCredentialsController extends StoragesController {
 	/**
 	 * @var UserProvided
 	 */
@@ -37,10 +44,22 @@ class UserCredentialsController extends Controller {
 	 */
 	private $userSession;
 
-	public function __construct($appName, IRequest $request, UserProvided $authMechanism, IUserSession $userSession) {
-		parent::__construct($appName, $request);
+	/**
+	 * @var UserGlobalStoragesService
+	 */
+	private $globalStoragesService;
+
+	public function __construct(
+		$appName, IRequest $request,
+		UserProvided $authMechanism,
+		IUserSession $userSession,
+		IL10N $l10n,
+		UserGlobalStoragesService $globalStoragesService
+	) {
+		parent::__construct($appName, $request, $l10n, $globalStoragesService);
 		$this->authMechanism = $authMechanism;
 		$this->userSession = $userSession;
+		$this->globalStoragesService = $globalStoragesService;
 	}
 
 	/**
@@ -49,8 +68,32 @@ class UserCredentialsController extends Controller {
 	 * @param string $password
 	 *
 	 * @NoAdminRequired
+	 * @return DataResponse
 	 */
 	public function store($storageId, $username, $password) {
 		$this->authMechanism->saveCredentials($this->userSession->getUser(), $storageId, $username, $password);
+
+		$storage = $this->globalStoragesService->getStorage($storageId);
+
+		$this->updateStorageStatus($storage);
+
+		$storage->setBackendOptions([]);
+		$storage->setMountOptions([]);
+		$this->manipulateStorageConfig($storage);
+
+
+		return new DataResponse(
+			$storage,
+			Http::STATUS_OK
+		);
+	}
+
+	protected function manipulateStorageConfig(StorageConfig $storage) {
+		/** @var AuthMechanism */
+		$authMechanism = $storage->getAuthMechanism();
+		$authMechanism->manipulateStorageConfig($storage, $this->userSession->getUser());
+		/** @var Backend */
+		$backend = $storage->getBackend();
+		$backend->manipulateStorageConfig($storage, $this->userSession->getUser());
 	}
 }
diff --git a/apps/files_external/controller/userstoragescontroller.php b/apps/files_external/controller/userstoragescontroller.php
index 741e906dec..ccf8bc24e0 100644
--- a/apps/files_external/controller/userstoragescontroller.php
+++ b/apps/files_external/controller/userstoragescontroller.php
@@ -25,6 +25,7 @@ namespace OCA\Files_External\Controller;
 
 use OCA\Files_External\Lib\Auth\AuthMechanism;
 use \OCP\IConfig;
+use OCP\IUser;
 use \OCP\IUserSession;
 use \OCP\IRequest;
 use \OCP\IL10N;
diff --git a/apps/files_external/js/settings.js b/apps/files_external/js/settings.js
index 756804238d..16576ce708 100644
--- a/apps/files_external/js/settings.js
+++ b/apps/files_external/js/settings.js
@@ -357,6 +357,9 @@ StorageConfig.prototype = {
 		if (this.mountPoint === '') {
 			return false;
 		}
+		if (!this.backend) {
+			return false;
+		}
 		if (this.errors) {
 			return false;
 		}
@@ -432,6 +435,48 @@ UserStorageConfig.prototype = _.extend({}, StorageConfig.prototype,
 	_url: 'apps/files_external/userstorages'
 });
 
+/**
+ * @class OCA.External.Settings.UserGlobalStorageConfig
+ * @augments OCA.External.Settings.StorageConfig
+ *
+ * @classdesc User external storage config
+ */
+var UserGlobalStorageConfig = function (id) {
+	this.id = id;
+};
+UserGlobalStorageConfig.prototype = _.extend({}, StorageConfig.prototype,
+	/** @lends OCA.External.Settings.UserStorageConfig.prototype */ {
+
+	_url: 'apps/files_external/userglobalstorages',
+
+	/**
+	 * Creates or saves the storage.
+	 *
+	 * @param {Function} [options.success] success callback, receives result as argument
+	 * @param {Function} [options.error] error callback
+	 */
+	save: function (options) {
+		var self = this;
+		var url = OC.generateUrl('apps/files_external/usercredentials/{id}', {id: this.id});
+
+		$.ajax({
+			type: 'PUT',
+			url: url,
+			contentType: 'application/json',
+			data: JSON.stringify({
+				username: this.backendOptions.user,
+				password: this.backendOptions.password
+			}),
+			success: function (result) {
+				if (_.isFunction(options.success)) {
+					options.success(result);
+				}
+			},
+			error: options.error
+		});
+	}
+});
+
 /**
  * @class OCA.External.Settings.MountOptionsDropdown
  *
@@ -748,7 +793,7 @@ MountConfigListView.prototype = _.extend({
 
 		$.each(authMechanismConfiguration['configuration'], _.partial(
 			this.writeParameterInput, $td, _, _, ['auth-param']
-		));
+		).bind(this));
 
 		this.trigger('selectAuthMechanism',
 			$tr, authMechanism, authMechanismConfiguration['scheme'], onCompletion
@@ -770,6 +815,7 @@ MountConfigListView.prototype = _.extend({
 		var $tr = this.$el.find('tr#addMountPoint');
 		this.$el.find('tbody').append($tr.clone());
 
+		$tr.data('storageConfig', storageConfig);
 		$tr.find('td').last().attr('class', 'remove');
 		$tr.find('td.mountOptionsToggle').removeClass('hidden');
 		$tr.find('td').last().removeAttr('style');
@@ -805,7 +851,7 @@ MountConfigListView.prototype = _.extend({
 		$tr.find('td.authentication').append(selectAuthMechanism);
 
 		var $td = $tr.find('td.configuration');
-		$.each(backend.configuration, _.partial(this.writeParameterInput, $td));
+		$.each(backend.configuration, _.partial(this.writeParameterInput, $td).bind(this));
 
 		this.trigger('selectBackend', $tr, backend.identifier, onCompletion);
 		this.configureAuthMechanism($tr, storageConfig.authMechanism, onCompletion);
@@ -866,8 +912,14 @@ MountConfigListView.prototype = _.extend({
 				success: function(result) {
 					var onCompletion = jQuery.Deferred();
 					$.each(result, function(i, storageParams) {
+						var storageConfig;
+						var isUserProvidedAuth = storageParams.authMechanism === 'password::userprovided';
 						storageParams.mountPoint = storageParams.mountPoint.substr(1); // trim leading slash
-						var storageConfig = new self._storageConfigClass();
+						if (isUserProvidedAuth) {
+							storageConfig = new UserGlobalStorageConfig();
+						} else {
+							storageConfig = new self._storageConfigClass();
+						}
 						_.extend(storageConfig, storageParams);
 						var $tr = self.newStorage(storageConfig, onCompletion);
 
@@ -878,12 +930,16 @@ MountConfigListView.prototype = _.extend({
 						var $authentication = $tr.find('.authentication');
 						$authentication.text($authentication.find('select option:selected').text());
 
-						// userglobal storages do not expose configuration data
-						$tr.find('.configuration').text(t('files_external', 'Admin defined'));
-
 						// disable any other inputs
 						$tr.find('.mountOptionsToggle, .remove').empty();
-						$tr.find('input, select, button').attr('disabled', 'disabled');
+						$tr.find('input:not(.user_provided), select:not(.user_provided)').attr('disabled', 'disabled');
+
+						if (isUserProvidedAuth) {
+							$tr.find('.configuration').find(':not(.user_provided)').remove();
+						} else {
+							// userglobal storages do not expose configuration data
+							$tr.find('.configuration').text(t('files_external', 'Admin defined'));
+						}
 					});
 					onCompletion.resolve();
 				}
@@ -918,22 +974,40 @@ MountConfigListView.prototype = _.extend({
 	 * @return {jQuery} newly created input
 	 */
 	writeParameterInput: function($td, parameter, placeholder, classes) {
+		var hasFlag = function(flag) {
+			return placeholder.indexOf(flag) !== -1;
+		};
 		classes = $.isArray(classes) ? classes : [];
 		classes.push('added');
 		if (placeholder.indexOf('&') === 0) {
 			classes.push('optional');
 			placeholder = placeholder.substring(1);
 		}
+
+		if (hasFlag('@')) {
+			if (this._isPersonal) {
+				classes.push('user_provided');
+			} else {
+				return;
+			}
+		}
+
 		var newElement;
-		if (placeholder.indexOf('*') === 0) {
-			newElement = $('<input type="password" class="'+classes.join(' ')+'" data-parameter="'+parameter+'" placeholder="'+placeholder.substring(1)+'" />');
-		} else if (placeholder.indexOf('!') === 0) {
+
+		var trimmedPlaceholder = placeholder;
+		var flags = ['@', '*', '!', '#', '&'];
+		while(flags.indexOf(trimmedPlaceholder[0]) !== -1) {
+			trimmedPlaceholder = trimmedPlaceholder.substr(1);
+		}
+		if (hasFlag('*')) {
+			newElement = $('<input type="password" class="'+classes.join(' ')+'" data-parameter="'+parameter+'" placeholder="'+ trimmedPlaceholder+'" />');
+		} else if (hasFlag('!')) {
 			var checkboxId = _.uniqueId('checkbox_');
-			newElement = $('<input type="checkbox" id="'+checkboxId+'" class="'+classes.join(' ')+'" data-parameter="'+parameter+'" /><label for="'+checkboxId+'">'+placeholder.substring(1)+'</label>');
-		} else if (placeholder.indexOf('#') === 0) {
+			newElement = $('<input type="checkbox" id="'+checkboxId+'" class="'+classes.join(' ')+'" data-parameter="'+parameter+'" /><label for="'+checkboxId+'">'+ trimmedPlaceholder+'</label>');
+		} else if (hasFlag('#')) {
 			newElement = $('<input type="hidden" class="'+classes.join(' ')+'" data-parameter="'+parameter+'" />');
 		} else {
-			newElement = $('<input type="text" class="'+classes.join(' ')+'" data-parameter="'+parameter+'" placeholder="'+placeholder+'" />');
+			newElement = $('<input type="text" class="'+classes.join(' ')+'" data-parameter="'+parameter+'" placeholder="'+ trimmedPlaceholder+'" />');
 		}
 		highlightInput(newElement);
 		$td.append(newElement);
@@ -952,7 +1026,12 @@ MountConfigListView.prototype = _.extend({
 			// new entry
 			storageId = null;
 		}
-		var storage = new this._storageConfigClass(storageId);
+
+		var storage = $tr.data('storageConfig');
+		if (!storage) {
+			storage = new this._storageConfigClass(storageId);
+		}
+		storage.errors = null;
 		storage.mountPoint = $tr.find('.mountPoint input').val();
 		storage.backend = $tr.find('.backend').data('identifier');
 		storage.authMechanism = $tr.find('.selectAuthMechanism').val();
@@ -966,7 +1045,7 @@ MountConfigListView.prototype = _.extend({
 			if ($input.attr('type') === 'button') {
 				return;
 			}
-			if (!isInputValid($input)) {
+			if (!isInputValid($input) && !$input.hasClass('optional')) {
 				missingOptions.push(parameter);
 				return;
 			}
@@ -994,7 +1073,7 @@ MountConfigListView.prototype = _.extend({
 			var users = [];
 			var multiselect = getSelection($tr);
 			$.each(multiselect, function(index, value) {
-				var pos = value.indexOf('(group)');
+				var pos = (value.indexOf)?value.indexOf('(group)'): -1;
 				if (pos !== -1) {
 					groups.push(value.substr(0, pos));
 				} else {
@@ -1057,7 +1136,9 @@ MountConfigListView.prototype = _.extend({
 	saveStorageConfig:function($tr, callback, concurrentTimer) {
 		var self = this;
 		var storage = this.getStorageConfig($tr);
-		if (!storage.validate()) {
+		console.log(storage);
+		if (!storage || !storage.validate()) {
+			console.log('invalid');
 			return false;
 		}
 
diff --git a/apps/files_external/lib/auth/password/userprovided.php b/apps/files_external/lib/auth/password/userprovided.php
index 8854513e16..b0ff50a279 100644
--- a/apps/files_external/lib/auth/password/userprovided.php
+++ b/apps/files_external/lib/auth/password/userprovided.php
@@ -21,6 +21,7 @@
 
 namespace OCA\Files_External\Lib\Auth\Password;
 
+use OCA\Files_External\Lib\DefinitionParameter;
 use OCP\IL10N;
 use OCP\IUser;
 use OCA\Files_External\Lib\Auth\AuthMechanism;
@@ -46,7 +47,13 @@ class UserProvided extends AuthMechanism {
 			->setIdentifier('password::userprovided')
 			->setScheme(self::SCHEME_PASSWORD)
 			->setText($l->t('User provided'))
-			->addParameters([]);
+			->addParameters([
+				(new DefinitionParameter('user', $l->t('Username')))
+					->setFlag(DefinitionParameter::FLAG_USER_PROVIDED),
+				(new DefinitionParameter('password', $l->t('Password')))
+					->setType(DefinitionParameter::VALUE_PASSWORD)
+					->setFlag(DefinitionParameter::FLAG_USER_PROVIDED),
+			]);
 	}
 
 	private function getCredentialsIdentifier($storageId) {
diff --git a/apps/files_external/lib/definitionparameter.php b/apps/files_external/lib/definitionparameter.php
index 59a098e632..85c3dd08ad 100644
--- a/apps/files_external/lib/definitionparameter.php
+++ b/apps/files_external/lib/definitionparameter.php
@@ -35,6 +35,7 @@ class DefinitionParameter implements \JsonSerializable {
 	/** Flag constants */
 	const FLAG_NONE = 0;
 	const FLAG_OPTIONAL = 1;
+	const FLAG_USER_PROVIDED = 2;
 
 	/** @var string name of parameter */
 	private $name;
@@ -121,7 +122,7 @@ class DefinitionParameter implements \JsonSerializable {
 	 * @return bool
 	 */
 	public function isFlagSet($flag) {
-		return (bool) $this->flags & $flag;
+		return (bool)($this->flags & $flag);
 	}
 
 	/**
@@ -143,10 +144,11 @@ class DefinitionParameter implements \JsonSerializable {
 				break;
 		}
 
-		switch ($this->getFlags()) {
-			case self::FLAG_OPTIONAL:
-				$prefix = '&' . $prefix;
-				break;
+		if ($this->isFlagSet(self::FLAG_OPTIONAL)) {
+			$prefix = '&' . $prefix;
+		}
+		if ($this->isFlagSet(self::FLAG_USER_PROVIDED)) {
+			$prefix = '@' . $prefix;
 		}
 
 		return $prefix . $this->getText();
@@ -160,28 +162,28 @@ class DefinitionParameter implements \JsonSerializable {
 	 * @return bool success
 	 */
 	public function validateValue(&$value) {
-		$optional = $this->getFlags() & self::FLAG_OPTIONAL;
+		$optional = $this->isFlagSet(self::FLAG_OPTIONAL) || $this->isFlagSet(self::FLAG_USER_PROVIDED);
 
 		switch ($this->getType()) {
-		case self::VALUE_BOOLEAN:
-			if (!is_bool($value)) {
-				switch ($value) {
-				case 'true':
-					$value = true;
-					break;
-				case 'false':
-					$value = false;
-					break;
-				default:
+			case self::VALUE_BOOLEAN:
+				if (!is_bool($value)) {
+					switch ($value) {
+						case 'true':
+							$value = true;
+							break;
+						case 'false':
+							$value = false;
+							break;
+						default:
+							return false;
+					}
+				}
+				break;
+			default:
+				if (!$value && !$optional) {
 					return false;
 				}
-			}
-			break;
-		default:
-			if (!$value && !$optional) {
-				return false;
-			}
-			break;
+				break;
 		}
 		return true;
 	}