Disable the plugin and DELETE IT.
What seems obvious too you ... is not for everybody.
What do you mean by DELETE ?
==> DELETE the extension from WP admin ?
or
==> DELETE the directory [wpforo] and all its files from the directory [plugins] ?
Same result. Delete it (not Uninstall it) from WP plugins admin or delete the wpForo folder via ftp.
Since you mention that it is not obvious for everybody (and that is true more or less), you must BACKUP everything EVEN when you update a plugin. YES. Even when updating a simple plugin. WP Backup is a simple procedure done via your Control Panel and takes 5 minutes or less.
Thank you for your answer and you help.
Backup is done (everyday) indeed.
Ok I did it.
But after instal, there is not theme active ... and I can not active it.
cf copy screen.
This theme is active, because this is the only one theme. I think this is a phrase problem, the phrase is changed incorrectly in phrase system or translated wrong in PO/Mo files. Please forget about wpForo themes, this is always active. Let check other issues. Do you see any issue on forum and what is the current status?
...
so in the directory [ wpf-themes ], I have :
- classic
- classic_2
I can see the forum on the web only with "classic_2" (after deleting "classic").
It doesn't function only with "classic" in [ wpf-themes ]
(I precise that I re instal wpforo as you asked me to)