diff --git a/tools/analyse.cpp b/tools/analyse.cpp
index efb84b4..c2ea8fa 100644
--- a/tools/analyse.cpp
+++ b/tools/analyse.cpp
@@ -192,9 +192,6 @@ int main (int argc, char const **argv)
 
     std::cerr << p << '\n';
 
-    std::ofstream output (argv[ARGS_OUTPUT], std::ios::out | std::ios::trunc);
-    output.exceptions (std::ios::badbit | std::ios::eofbit | std::ios::failbit);
-
     // Find all the chunks and prepare them for output
     std::cout << "processing\n";
     std::vector<emory::chunk::region> src = find_chunks (argv[ARGS_INPUT], p);
@@ -203,6 +200,8 @@ int main (int argc, char const **argv)
     std::sort (src.begin (), src.end (), region_less);
 
     // Write all chunks to the output file
+    std::ofstream output (argv[ARGS_OUTPUT], std::ios::out | std::ios::trunc);
+    output.exceptions (std::ios::badbit | std::ios::eofbit | std::ios::failbit);
     output << "params: " << p << '\n';
     for (auto const &chunk: src) {
         output << chunk.size() << ' ';