Index: src/libchcore/TSubTaskCopyMove.cpp
===================================================================
diff -u -N -re8f31b0f922b402878356e130c866c4f3682a7f5 -rc6022cc2c68d1f286097697f4ba65098b92db222
--- src/libchcore/TSubTaskCopyMove.cpp	(.../TSubTaskCopyMove.cpp)	(revision e8f31b0f922b402878356e130c866c4f3682a7f5)
+++ src/libchcore/TSubTaskCopyMove.cpp	(.../TSubTaskCopyMove.cpp)	(revision c6022cc2c68d1f286097697f4ba65098b92db222)
@@ -665,6 +665,13 @@
 			return TSubTaskBase::eSubResult_Continue;
 		}
 
+		// ullSeekTo contains the seek position in destination file; in case the destination is already
+		// larger than source file all we can do is to perform truncation of destination file to the size of
+		// source file.
+		// NOTE: the truncation that will be the result of the following assignment might cause the end of destination file
+		// to be overwritten by the end of source file.
+		ullSeekTo = std::min(ullSeekTo, fsNewSize);
+
 		// seek to the position where copying will start
 		file_size_t fsMoveTo = spFileDst->GetSeekPositionForResume(ullSeekTo);