diff --git a/snappymail/v/0.0.0/app/libraries/MailSo/Imap/ImapClient.php b/snappymail/v/0.0.0/app/libraries/MailSo/Imap/ImapClient.php
index 4bd00ba4a..c406920a5 100644
--- a/snappymail/v/0.0.0/app/libraries/MailSo/Imap/ImapClient.php
+++ b/snappymail/v/0.0.0/app/libraries/MailSo/Imap/ImapClient.php
@@ -527,6 +527,16 @@ class ImapClient extends \MailSo\Net\NetClient
 		return $this->specificFolderList(false, $sParentFolderName, $sListPattern, true);
 	}
 
+	/**
+	 * @throws \MailSo\Net\Exceptions\Exception
+	 * @throws \MailSo\Imap\Exceptions\Exception
+	 */
+	public function FolderHierarchyDelimiter(string $sFolderName = '') : ?string
+	{
+		$oResponse = $this->SendRequestGetResponse('LIST', ['""', $this->EscapeString($sParentFolderName)]);
+		return ('LIST' === $oResponse[0]->ResponseList[1]) ? $oResponse[0]->ResponseList[3] : null;
+	}
+
 	/**
 	 * @throws \MailSo\Base\Exceptions\InvalidArgumentException
 	 * @throws \MailSo\Net\Exceptions\Exception
diff --git a/snappymail/v/0.0.0/app/libraries/MailSo/Mail/MailClient.php b/snappymail/v/0.0.0/app/libraries/MailSo/Mail/MailClient.php
index f7e249082..49723296d 100644
--- a/snappymail/v/0.0.0/app/libraries/MailSo/Mail/MailClient.php
+++ b/snappymail/v/0.0.0/app/libraries/MailSo/Mail/MailClient.php
@@ -2056,8 +2056,8 @@ class MailClient
 
 		if (!\strlen($sDelimiter) || \strlen($sFolderParentFullNameRaw))
 		{
-			$aFolders = $this->oImapClient->FolderList('', \strlen($sFolderParentFullNameRaw) ? $sFolderParentFullNameRaw : 'INBOX');
-			if (!$aFolders)
+			$sDelimiter = $this->oImapClient->FolderHierarchyDelimiter($sFolderParentFullNameRaw);
+			if (null === $sDelimiter)
 			{
 				// TODO: Translate
 				throw new Exceptions\RuntimeException(
@@ -2066,7 +2066,6 @@ class MailClient
 						: 'Cannot get folder delimiter.');
 			}
 
-			$sDelimiter = $aFolders[0]->Delimiter();
 			if (\strlen($sDelimiter) && \strlen($sFolderParentFullNameRaw))
 			{
 				$sFolderParentFullNameRaw .= $sDelimiter;
@@ -2114,6 +2113,7 @@ class MailClient
 
 	/**
 	 * @throws \MailSo\Base\Exceptions\InvalidArgumentException
+	 * @throws \MailSo\Base\Exceptions\RuntimeException
 	 */
 	protected function folderModify(string $sPrevFolderFullNameRaw, string $sNextFolderNameInUtf, bool $bRename, bool $bSubscribeOnModify) : self
 	{