diff --git a/infer/lib/python/infer b/infer/lib/python/infer
index 81b34f5b7..1bb87f0ee 100755
--- a/infer/lib/python/infer
+++ b/infer/lib/python/infer
@@ -121,6 +121,7 @@ def main():
 
     if imported_module:
         analyze.create_results_dir(args.infer_out)
+        analyze.reset_start_file(args.infer_out)
 
         utils.configure_logging(args)
         logging.info('Running command %s', ' '.join(sys.argv))
diff --git a/infer/lib/python/inferlib/analyze.py b/infer/lib/python/inferlib/analyze.py
index 489cf910e..9152be3f8 100644
--- a/infer/lib/python/inferlib/analyze.py
+++ b/infer/lib/python/inferlib/analyze.py
@@ -198,6 +198,11 @@ def create_results_dir(results_dir):
     utils.mkdir_if_not_exists(os.path.join(results_dir, 'sources'))
 
 
+def reset_start_file(results_dir):
+    # create new empty file - this will update modified timestamp
+    open(os.path.join(results_dir, '.start'), 'w').close()
+
+
 def clean(infer_out):
     directories = ['multicore', 'classnames', 'sources', jwlib.FILELISTS]
     extensions = ['.cfg', '.cg']
diff --git a/infer/src/backend/DB.ml b/infer/src/backend/DB.ml
index b5ceb22da..3185dadae 100644
--- a/infer/src/backend/DB.ml
+++ b/infer/src/backend/DB.ml
@@ -332,3 +332,15 @@ let is_source_file path =
   IList.exists
     (fun ext -> Filename.check_suffix path ext)
     Config.source_file_extentions
+
+let infer_start_time = lazy
+  (file_modified_time (Results_dir.path_to_filename Results_dir.Abs_root [Config.start_filename]))
+
+(** Return whether filename was updated after analysis started. File doesn't have to exist *)
+let file_was_updated_after_start fname =
+  if file_exists fname then
+    let file_mtime = file_modified_time fname in
+    file_mtime >= Lazy.force infer_start_time
+  else
+    (* since file doesn't exist, it wasn't modified *)
+    false
diff --git a/infer/src/backend/DB.mli b/infer/src/backend/DB.mli
index 4aa754986..ff305f204 100644
--- a/infer/src/backend/DB.mli
+++ b/infer/src/backend/DB.mli
@@ -27,6 +27,8 @@ val filename_add_suffix : filename -> string -> filename
 val file_exists : filename -> bool
 val file_remove : filename -> unit
 val file_modified_time : filename -> float (** Return the time when a file was last modified. The file must exist. *)
+(** Return whether filename was updated after analysis started. File doesn't have to exist *)
+val file_was_updated_after_start : filename -> bool
 
 (** {2 Results Directory} *)
 
diff --git a/infer/src/backend/config.ml b/infer/src/backend/config.ml
index 12e0828c2..cedb7daf9 100644
--- a/infer/src/backend/config.ml
+++ b/infer/src/backend/config.ml
@@ -396,6 +396,8 @@ let weak = "<\"Weak\">"
 
 let assign = "<\"Assign\">"
 
+let start_filename = ".start"
+
 (** Programming language. *)
 type language = C_CPP | Java