I was running CiviCRM 5.16 on top of Drupal 7.69, atop Debian 9. I tried installing the GoCardless extension (after discussion at CiviCamp Birmingham) using the built-in extensions manager and couldn't quite get it to work. I figured it might be because my CiviCRM was a bit too old, so I tried removing it and upgrading Civi to 5.23.1, then reinstalling the extension.
Somewhere in this upgrade process, I've got to the point where the CiviCRM menu bar and dashboard no longer appear on my site. Everything seems to work if I can remember the URLs, but this is obviously very frustrating. Any idea where to look? I'm not getting any browser errors, and the last thing in
ConfigAndLog/CiviCRM.*.log is the database upgrade to 5.23.1