diff --git a/MoveTask.cpp b/MoveTask.cpp
index 38cca04..ea64a1c 100644
--- a/MoveTask.cpp
+++ b/MoveTask.cpp
@@ -128,6 +128,12 @@
     uint64_t expectedBytes = GetTreeBytes(fromPath);
     uint64_t startFreeBytes = GetFreeBytes(toPath);
 
+    if (expectedBytes > startFreeBytes) {
+        LOG(ERROR) << "Data size " << expectedBytes << " is too large to fit in free space "
+                << startFreeBytes;
+        return -1;
+    }
+
     std::vector<std::string> cmd;
     cmd.push_back(kCpPath);
     cmd.push_back("-p"); /* preserve timestamps, ownership, and permissions */