diff --git a/src/dos/dos_memory.cpp b/src/dos/dos_memory.cpp
index 2279c216..e2e3d9d3 100644
--- a/src/dos/dos_memory.cpp
+++ b/src/dos/dos_memory.cpp
@@ -165,6 +165,11 @@ bool DOS_ResizeMemory(Bit16u segment,Bit16u * blocks) {
 
 bool DOS_FreeMemory(Bit16u segment) {
 //TODO Check if allowed to free this segment
+	if ((segment-1) < MEM_START){
+		LOG(LOG_DOSMISC,LOG_ERROR)("Program tried to free %X ---ERROR",segment);
+		return false;
+	}
+      
 	DOS_MCB mcb(segment-1);
 	mcb.SetPSPSeg(MCB_FREE);
 	DOS_CompressMemory();