diff --git a/libs/main/io_utils/pifiletransfer.cpp b/libs/main/io_utils/pifiletransfer.cpp
index 7389a769..acdeac73 100644
--- a/libs/main/io_utils/pifiletransfer.cpp
+++ b/libs/main/io_utils/pifiletransfer.cpp
@@ -131,6 +131,12 @@ bool PIFileTransfer::sendFiles(const PIVector<PFTFileInfo> & files) {
 
 void PIFileTransfer::processFile(int id, ullong start, PIByteArray & data) {
 	// piCout << "processFile" << id << files_.size();
+	if (id <= 0 || id > files_.size_s()) {
+		cur_file_string = "Error: Invalid file id " + PIString::fromNumber(id);
+		piCoutObj << cur_file_string;
+		stopReceive();
+		return;
+	}
 	PFTFileInfo fi  = files_[id - 1];
 	bytes_file_all  = fi.size;
 	bytes_file_cur  = start;