diff --git a/src/vmime/net/imap/IMAPFolder.cpp b/src/vmime/net/imap/IMAPFolder.cpp
index 751c84dc..98bc05d8 100644
--- a/src/vmime/net/imap/IMAPFolder.cpp
+++ b/src/vmime/net/imap/IMAPFolder.cpp
@@ -1061,7 +1061,7 @@ void IMAPFolder::setMessageFlags(
 
 	const std::vector <string> flagList = IMAPUtils::messageFlagList(flags);
 
-	if (!flagList.empty()) {
+	if ((mode == message::FLAG_MODE_SET) || !flagList.empty()) {
 
 		// Send the request
 		IMAPCommand::STORE(msgs, mode, flagList)->send(m_connection);