I had 5 plugins with updates. After updating all of them through the Available Updates tool they disappeared from the Network Plugins page. I received errors like this for all plugins:
The plugin custom-post-type-ui/custom-post-type-ui.php has been deactivated due to an error: Plugin file does not exist.
The folders still exist in /wp-content/plugins/
When I deleted the folders and uploaded them through FTP they do not appear on the Plugins page. When I install them through wp-admin I receive this log text:
Downloading install package from http://downloads.wordpress.org/plugin/custom-post-type-ui.zipâ¦
Unpacking the packageâ¦
Installing the pluginâ¦
Successfully installed the plugin Custom Post Type UI 0.7.1.
Network Activate | Return to Plugin Installer
But when I click Network Activate, I receive this error:
The plugin does not have a valid header.
This happens for all 5 plugins and only happened beginning today.
We resolved this issue by removing re-uploading the admin and includes folders, although I’m not sure what originally caused the issue.
To resolve this error
The plugin does not have a valid header.
you need to check your plugins file, there might be some white space before or after<?php
and?>
Remove those spaces, then the error
The plugin does not have a valid header.
wont display