This (general) problem (see below) has been fixed in r108758 https://www.mediawiki.org/wiki/Special:Code/MediaWiki/108758 Aaron, thanks! original problem report was: When I run php update.php --conf path-to-my-LocalSettings.php to upgrade from 1.15.1 MediaWiki to trunk, I get this reproducible message at the end ( after having set $wgShowExceptionDetails = true; ) Populating img_sha1 field FSFile::__construct given storage path `mwstore://local-backend/local-public/a/a1/afilenname.jpg`. Backtrace: #0 /srv/phase3/includes/filerepo/file/File.php(1637): FSFile->__construct('mwstore://local...' #1 /srv/phase3/maintenance/populateImageSha1.php(97): File::sha1Base36('mwstore://local...') #2 /srv/phase3/maintenance/Maintenance.php(1277): PopulateImageSha1->doDBUpdates() #3 /srv/phase3/maintenance/populateImageSha1.php(46): LoggedUpdateMaintenance->execute() #4 /srv/phase3/maintenance/update.php(128): PopulateImageSha1->execute() #5 /srv/phase3/maintenance/doMaintenance.php(105): UpdateMediaWiki->execute() #6 /srv/phase3/maintenance/update.php(151): require_once('/srv/...') #7 {main} Is there a known problem with the update.php updater regarding the img_sha1 calculation, or another problem what has to do with mwstore:// ?