I updated the plugin to version 3.0.5 on about 20 sites. On several of them, the plugin was deactivated. When I try to reactivate, I get this error above the list of plugins:
The plugin backwpup/backwpup.php has been deactivated due to an error: Plugin file does not exist.
I checked via FTP, and the wp-content/plugins/backwpup/ directory is there, but it's either empty or nearly empty (such as only an sdk directory).
I updated the sites using WP Remote, but I don't think that caused the problem.