diff --git a/Changelog.draft.rst b/Changelog.draft.rst
index 76a0ea3..d9aa0bf 100644
--- a/Changelog.draft.rst
+++ b/Changelog.draft.rst
@@ -18,3 +18,8 @@ Changes
 
 Bug Fixes
 ---------
+
+* IMAP<->IMAP sync with a readonly local IMAP repository failed with a
+  rather mysterious "TypeError: expected a character buffer object"
+  error. Fix this my retrieving the list of folders early enough even
+  for readonly repositories.
diff --git a/offlineimap/accounts.py b/offlineimap/accounts.py
index 71f08fe..d476b3e 100644
--- a/offlineimap/accounts.py
+++ b/offlineimap/accounts.py
@@ -265,6 +265,13 @@ class SyncableAccount(Account):
             remoterepos = self.remoterepos
             localrepos = self.localrepos
             statusrepos = self.statusrepos
+
+            # init repos with list of folders, so we have them (and the
+            # folder delimiter etc)
+            remoterepos.getfolders()
+            localrepos.getfolders()
+            statusrepos.getfolders()
+
             # replicate the folderstructure between REMOTE to LOCAL
             if not localrepos.getconfboolean('readonly', False):
                 self.ui.syncfolders(remoterepos, localrepos)