diff --git a/runbot/models/build.py b/runbot/models/build.py
index 2479396f..f4b0b09b 100644
--- a/runbot/models/build.py
+++ b/runbot/models/build.py
@@ -329,6 +329,8 @@ class BuildResult(models.Model):
             build_by_old_values = defaultdict(lambda: self.env['runbot.build'])
             for record in self:
                 build_by_old_values[record.local_state] += record
+            if values['local_state'] == 'done':
+                self.env['runbot.commit.export'].search([('build_id', 'in', self.ids)]).unlink()
         local_result = values.get('local_result')
         for build in self:
             if local_result and local_result != self._get_worst_result([build.local_result, local_result]):  # dont write ok on a warn/error build
@@ -729,8 +731,6 @@ class BuildResult(models.Model):
                 build._github_status()
             build._run_job()
 
-            if build.local_state == 'done':
-                self.env['runbot.commit.export'].search([('build_id', '=', build.id)]).unlink()
 
     def _run_job(self):
         # run job
diff --git a/runbot/models/commit.py b/runbot/models/commit.py
index cb12b378..e2e3d0d4 100644
--- a/runbot/models/commit.py
+++ b/runbot/models/commit.py
@@ -56,7 +56,8 @@ class Commit(models.Model):
         """Export a git repo into a sources"""
         #  TODO add automated tests
         self.ensure_one()
-        self.env['runbot.commit.export'].create({'commit_id': self.id, 'build_id': build.id})
+        if not self.env['runbot.commit.export'].search([('build_id', '=', build.id), ('commit_id', '=', self.id)]):
+            self.env['runbot.commit.export'].create({'commit_id': self.id, 'build_id': build.id})
         export_path = self._source_path()
 
         if os.path.isdir(export_path):