diff --git a/src/add-ons/mail_daemon/inbound_protocols/imap/imap_lib/IMAPProtocol.cpp b/src/add-ons/mail_daemon/inbound_protocols/imap/imap_lib/IMAPProtocol.cpp
index 8255cc84e4..cc85a3faef 100644
--- a/src/add-ons/mail_daemon/inbound_protocols/imap/imap_lib/IMAPProtocol.cpp
+++ b/src/add-ons/mail_daemon/inbound_protocols/imap/imap_lib/IMAPProtocol.cpp
@@ -24,7 +24,7 @@ ConnectionReader::ConnectionReader(ServerConnection* connection)
 
 status_t
 ConnectionReader::GetNextLine(BString& line, bigtime_t timeout,
-	uint32 minUnfinishedLine)
+	int32 maxUnfinishedLine)
 {
 	line.SetTo((const char*)NULL, 0);
 
@@ -33,7 +33,7 @@ ConnectionReader::GetNextLine(BString& line, bigtime_t timeout,
 		if (status == B_OK)
 			return status;
 		if (status == B_NAME_NOT_FOUND) {
-			if (line.Length() < (int32)minUnfinishedLine)
+			if (maxUnfinishedLine < 0 || line.Length() < maxUnfinishedLine)
 				continue;
 			else
 				return status;
diff --git a/src/add-ons/mail_daemon/inbound_protocols/imap/imap_lib/IMAPProtocol.h b/src/add-ons/mail_daemon/inbound_protocols/imap/imap_lib/IMAPProtocol.h
index 82d6620e1c..df8beb56f9 100644
--- a/src/add-ons/mail_daemon/inbound_protocols/imap/imap_lib/IMAPProtocol.h
+++ b/src/add-ons/mail_daemon/inbound_protocols/imap/imap_lib/IMAPProtocol.h
@@ -32,7 +32,7 @@ public:
 			minUnfinishedLine characters are returned. */
 			status_t			GetNextLine(BString& line,
 									bigtime_t timeout = kIMAP4ClientTimeout,
-									uint32 minUnfinishedLine = 128);
+									int32 maxUnfinishedLine = -1);
 			/*! Read data and append it to line till the end of file is
 			reached. */
 			status_t			FinishLine(BString& line);