diff --git a/offlineimap.conf b/offlineimap.conf
index 7fbbdf7..c447d7b 100644
--- a/offlineimap.conf
+++ b/offlineimap.conf
@@ -182,6 +182,13 @@ accounts = Test
 # The header, peritem, sep, and footer are all Python expressions passed
 # through eval, so you can (and must) use Python quoting.
 #
+# The incremental setting controls whether the file is written after each
+# account completes or once all synced accounts are complete. This is usefull if
+# an account is sightly slower than the other. It allows keeping the previous
+# file rather than having it partially written.
+# This works best with "no" if in one-shot mode started by cron or systemd
+# timers. Default: no.
+#
 # The following hash key are available to the expansion for 'peritem':
 # - accountname: the name of the corresponding account;
 # - foldername: the name of the folder;
@@ -197,6 +204,7 @@ accounts = Test
 #peritem = "+%(accountname)s/%(foldername)s"
 #sep = " "
 #footer = "\n"
+#incremental = no
 
 
 # This option stands in the [mbnames] section.
diff --git a/offlineimap/accounts.py b/offlineimap/accounts.py
index 62ed5c3..cac4d88 100644
--- a/offlineimap/accounts.py
+++ b/offlineimap/accounts.py
@@ -359,7 +359,7 @@ class SyncableAccount(Account):
                 thr.join()
             # Write out mailbox names if required and not in dry-run mode
             if not self.dryrun:
-                mbnames.write()
+                mbnames.write(False)
             localrepos.forgetfolders()
             remoterepos.forgetfolders()
         except:
diff --git a/offlineimap/init.py b/offlineimap/init.py
index a5277cb..a48c152 100644
--- a/offlineimap/init.py
+++ b/offlineimap/init.py
@@ -334,6 +334,10 @@ class OfflineImap:
                                            'config': self.config})
                 t.start()
                 threadutil.exitnotifymonitorloop(threadutil.threadexited)
+
+            if not options.dryrun:
+                offlineimap.mbnames.write(True)
+
             self.ui.terminate()
         except (SystemExit):
             raise
diff --git a/offlineimap/mbnames.py b/offlineimap/mbnames.py
index 936a110..8829ee5 100644
--- a/offlineimap/mbnames.py
+++ b/offlineimap/mbnames.py
@@ -38,7 +38,17 @@ def add(accountname, foldername, localfolders):
     if not foldername in boxes[accountname]:
         boxes[accountname].append(foldername)
 
-def write():
+def write(allcomplete):
+    incremental = config.getdefaultboolean("mbnames", "incremental", False)
+
+    # Skip writing if we don't want incremental writing and we're not done.
+    if not incremental and not allcomplete:
+        return
+
+    # Skip writing if we want incremental writing and we're done.
+    if incremental and allcomplete:
+        return
+
     # See if we're ready to write it out.
     for account in accounts:
         if account not in boxes: