Did you try reinstalling them? Do you have a picture, video, or error code?
Yes, I tried to reinstall them, but then an error appears saying the folder already exists (which is true).
That said there’s no other error. The plugin panel on the dashboard is just empty like there wouldn’t be any plugins in the folder.
Now WordPress 4.0 was released and I hoped this would fix the problem – so I updated. But the plugin problem is still there. 🙁
After downgrading I realized the plugins get still blocked. This time I got to know the reason “The plugin was deactived. The header isn’t valid.”
So I looked into my plugins and understood what about the header was wrong…
I’ve been infected with malware. 🙁
This is exactly the same case: http://wordpress.org/support/topic/7-website-same-error-the-plugin-does-not-have-a-valid-header
Thank you for your help though. It had nothing to do with the update. After the update I just clicked on the plugins section on the dashboard and the plugins got deactivated by WordPress automatically (fortunately).
