diff --git a/tests/tine20/Admin/Frontend/Json/EmailAccountTest.php b/tests/tine20/Admin/Frontend/Json/EmailAccountTest.php
index 5e9de5ad646..8081f0cceef 100644
--- a/tests/tine20/Admin/Frontend/Json/EmailAccountTest.php
+++ b/tests/tine20/Admin/Frontend/Json/EmailAccountTest.php
@@ -94,7 +94,7 @@ public function testEmailAccountApi()
      * @param array $data
      * @return array
      */
-    public static function getSharedAccountData($sendgrant = true, $data = [])
+    public static function getSharedAccountData(bool $sendgrant = true, array $data = [])
     {
         return array_merge([
             'name' => 'unittest shared account',
diff --git a/tests/tine20/Felamimail/Frontend/JsonTest.php b/tests/tine20/Felamimail/Frontend/JsonTest.php
index cef789bcb00..bc9535b487e 100644
--- a/tests/tine20/Felamimail/Frontend/JsonTest.php
+++ b/tests/tine20/Felamimail/Frontend/JsonTest.php
@@ -1286,7 +1286,7 @@ public function testForwardAttachmentCachePdf()
             'attachments'   => $messageToSend['attachments']
         ));
         Felamimail_Controller_Message_Send::getInstance()->sendMessage($forwardMessage);
-        
+
         $forwardMessage = $this->_searchForMessageBySubject('test forward with attachmnets');
         $this->_foldersToClear = array('INBOX', $this->_account->sent_folder);
         $fullMessage = Felamimail_Controller_Message::getInstance()->getCompleteMessage($forwardMessage['id']);
@@ -3248,7 +3248,70 @@ public function testMoveFolder()
         $testFolder = Felamimail_Controller_Folder::getInstance()->getByBackendAndGlobalName($this->_account, $this->_testFolderName);
         self::assertEquals(1, $testFolder->has_children, 'has_children should be 1');
     }
-    
+
+    /**
+     * 1. Folder "A" unter der Inbox erstellen.
+     * 2. Bei beiden Usern die Ordnerliste aktualisieren.
+     * 3. Bei UserA den Folder "A" löschen.
+     * 4. Bei UserB den Folder "B" unter den Folder "A" erstellen.
+     * 5. Bei beiden Usern die Ordnerliste aktualisieren.
+     *
+     * @return void
+     * @throws Tinebase_Exception_AccessDenied
+     * @throws Tinebase_Exception_InvalidArgument
+     * @throws Tinebase_Exception_NotFound
+     * @throws Tinebase_Exception_Record_DefinitionFailure
+     * @throws Tinebase_Exception_Record_Validation
+     */
+    public function testDeleteFolderWithAnotherUserInSharedAccount()
+    {
+        $parent = 'INBOX';
+        $testFolder = 'subfolder';
+        $jsmith = $this->_personas['jsmith'];
+        $account = $this->_createSharedAccount(true, [
+            'grants' => [
+                [
+                    'readGrant' => true,
+                    'editGrant' => true,
+                    'addGrant' => true,
+                    'account_type' => 'user',
+                    'account_id' => Tinebase_Core::getUser()->getId(),
+                ], [
+                    'readGrant' => true,
+                    'editGrant' => true,
+                    'addGrant' => true,
+                    'account_type' => 'user',
+                    'account_id' => $jsmith->getId(),
+                ]
+            ]
+        ]);
+
+        try {
+            $this->_json->addFolder($parent, '', $account->getId());
+        } catch (Tinebase_Exception_SystemGeneric $tesg) {
+            // already exists
+        }
+        $folder = $this->_json->addFolder($testFolder, $parent, $account->getId());
+        $testFolderGlobalname = $folder['globalname'];
+
+        $this->_json->updateFolderCache($account->getId(), $parent);
+        Tinebase_Core::setUser($jsmith);
+        $this->_json->updateFolderCache($account->getId(), $parent);
+        Tinebase_Core::setUser($this->_originalTestUser);
+        $this->_json->deleteFolder($testFolderGlobalname, $account->getId());
+        Tinebase_Core::setUser($jsmith);
+        try {
+            $this->_json->addFolder('subfolder2', $testFolderGlobalname, $account->getId());
+            $result = $this->_json->updateFolderCache($account->getId(), $parent);
+            $folder = $result[0];
+            self::assertEquals(1, $folder['is_selectable'], 'folder should be selectable (or removed!): '
+                . print_r($folder, true));
+        } catch (Tinebase_Exception_NotFound $tenf) {
+            self::assertEquals('Could not create folder: parent folder INBOX.subfolder not found',
+                $tenf->getMessage());
+        }
+    }
+
     public function testRefreshFolder()
     {
         $folder = $this->_getFolder($this->_testFolderName);
diff --git a/tests/tine20/Felamimail/TestCase.php b/tests/tine20/Felamimail/TestCase.php
index 20b44875321..36c7a728f3e 100644
--- a/tests/tine20/Felamimail/TestCase.php
+++ b/tests/tine20/Felamimail/TestCase.php
@@ -514,17 +514,18 @@ protected function _sieveTestHelper(array $_sieveData, bool $_isMime = false, ?s
 
     /**
      * @param bool $sendgrant
-     * @return Tinebase_Record_Interface
+     * @return Felamimail_Model_Account
      * @throws Tinebase_Exception_AccessDenied
      * @throws Tinebase_Exception_InvalidArgument
      * @throws Tinebase_Exception_NotFound
      * @throws Tinebase_Exception_Record_DefinitionFailure
      * @throws Tinebase_Exception_Record_Validation
      */
-    protected function _createSharedAccount($sendgrant = true)
+    protected function _createSharedAccount(bool $sendgrant = true, array $data = [])
     {
         Tinebase_EmailUser::clearCaches();
-        $sharedAccountData = Admin_Frontend_Json_EmailAccountTest::getSharedAccountData($sendgrant);
+        $sharedAccountData = Admin_Frontend_Json_EmailAccountTest::getSharedAccountData($sendgrant, $data);
+        /* @var Felamimail_Model_Account $sharedAccount */
         $sharedAccount = Admin_Controller_EmailAccount::getInstance()->create(new Felamimail_Model_Account($sharedAccountData));
         // we need to commit so imap user is in imap db
         Tinebase_TransactionManager::getInstance()->commitTransaction($this->_transactionId);
diff --git a/tine20/Felamimail/Backend/ImapProxy.php b/tine20/Felamimail/Backend/ImapProxy.php
index 69196d569c1..c33a1540958 100644
--- a/tine20/Felamimail/Backend/ImapProxy.php
+++ b/tine20/Felamimail/Backend/ImapProxy.php
@@ -23,6 +23,7 @@
  * @method examineFolder($globalName)
  * @method removeMessage($id)
  * @method getChangedFlags($modseq)
+ * @method createFolder($name, $parentFolder = null, $_delimiter = '/')
  */
 class Felamimail_Backend_ImapProxy
 {
diff --git a/tine20/Felamimail/Controller/Folder.php b/tine20/Felamimail/Controller/Folder.php
index 57676289b32..8d9078213c7 100644
--- a/tine20/Felamimail/Controller/Folder.php
+++ b/tine20/Felamimail/Controller/Folder.php
@@ -215,27 +215,46 @@ public function getByBackendAndGlobalName($_accountId, $_globalName)
      * create folder
      *
      * @param string|Felamimail_Model_Account $_accountId
-     * @param string $_folderName to create
-     * @param string $_parentFolder parent folder globalname
+     * @param string $_folderName
+     * @param string $_parentFolder
      * @return Felamimail_Model_Folder
+     * @throws Felamimail_Exception
+     * @throws Felamimail_Exception_IMAPInvalidCredentials
      * @throws Felamimail_Exception_IMAPServiceUnavailable
+     * @throws Tinebase_Exception_NotFound
+     * @throws Tinebase_Exception_Record_DefinitionFailure
+     * @throws Tinebase_Exception_Record_Validation
      * @throws Tinebase_Exception_SystemGeneric
      */
-    public function create($_accountId, $_folderName, $_parentFolder = '')
+    public function create($_accountId, string $_folderName, string $_parentFolder = ''): Felamimail_Model_Folder
     {
-        $account = ($_accountId instanceof Felamimail_Model_Account) ? $_accountId : Felamimail_Controller_Account::getInstance()->get($_accountId);
+        $account = ($_accountId instanceof Felamimail_Model_Account)
+            ? $_accountId
+            : Felamimail_Controller_Account::getInstance()->get($_accountId);
         $this->_delimiter = $account->delimiter;
         
         $foldername = $this->_prepareFolderName($_folderName);
         $globalname = (empty($_parentFolder)) ? $foldername : $_parentFolder . $this->_delimiter . $foldername;
-        if (Tinebase_Core::isLogLevel(Zend_Log::DEBUG)) Tinebase_Core::getLogger()->debug(__METHOD__ . '::' . __LINE__ . ' Trying to create new folder: ' . $globalname . ' (parent: ' . $_parentFolder . ')');
+        if (Tinebase_Core::isLogLevel(Zend_Log::DEBUG)) Tinebase_Core::getLogger()->debug(
+            __METHOD__ . '::' . __LINE__ . ' Trying to create new folder: ' . $globalname
+            . ' (parent: ' . $_parentFolder . ')');
         
         $imap = Felamimail_Backend_ImapFactory::factory($account);
-        
+
+        // check if parent folder exists
+        if (! empty($_parentFolder)) {
+            try {
+                $imap->examineFolder($_parentFolder);
+            } catch (Zend_Mail_Storage_Exception $zmse) {
+                throw new Tinebase_Exception_NotFound('Could not create folder: parent folder '
+                    . $_parentFolder . ' not found');
+            }
+        }
+
         try {
             $imap->createFolder(
                 Felamimail_Model_Folder::encodeFolderName($foldername), 
-                (empty($_parentFolder)) ? NULL : Felamimail_Model_Folder::encodeFolderName($_parentFolder), 
+                (empty($_parentFolder)) ? null : Felamimail_Model_Folder::encodeFolderName($_parentFolder),
                 $this->_delimiter
             );
 
@@ -247,7 +266,8 @@ public function create($_accountId, $_folderName, $_parentFolder = '')
                 'parent' => $_parentFolder,
             ));
             $folder->supports_condstore = $this->supportsCondStore($folder, $account, $imap);
-            
+
+            /* @var Felamimail_Model_Folder $folder */
             $folder = $this->_backend->create($folder);
             
             if (Tinebase_Core::isLogLevel(Zend_Log::INFO)) Tinebase_Core::getLogger()->info(
@@ -256,12 +276,13 @@ public function create($_accountId, $_folderName, $_parentFolder = '')
         } catch (Zend_Mail_Storage_Exception $zmse) {
             // perhaps the folder already exists
             if (Tinebase_Core::isLogLevel(Zend_Log::INFO)) Tinebase_Core::getLogger()->info(
-                __METHOD__ . '::' . __LINE__ . ' Could not create new folder: ' . $globalname . ' (' . $zmse->getMessage() . ')');
+                __METHOD__ . '::' . __LINE__ . ' Could not create new folder: ' . $globalname
+                . ' (' . $zmse->getMessage() . ')');
             
             // reload folder cache of parent
             $parentSubs = $this->_cacheController->update($account, $_parentFolder);
             $folder = $parentSubs->filter('globalname', $globalname)->getFirstRecord();
-            if ($folder === NULL) {
+            if ($folder === null) {
                 throw new Felamimail_Exception_IMAPServiceUnavailable($zmse->getMessage());
             }