@peter
Not sure but i think it happened because while updating plugin it failed to properly activate itself therefor fatal error occurred. What we have done is manually activated plugin.
That’s all i know, wordpress developer or any geek can explain it well.
Solution:
Go to /wp-content/plugins/w3-total-cache/inc/functions/
Look for activation.php and
Open it in code editor through your Cpanel or FTP access.
At beginning of line no. 127 type: /* and at the end type */
it looks like –
/*throw new FileOperationException($error, ‘read’, ‘file’, $path);*/
Save the file.
Now you can login to dashboard, deactivate w3 total cache plugin.
Now remove the /* and */ you added before,
save the file again.
Go to dashboard activate plugin and you’re good to go
[Via] member VivaWP, Thread: http://wordpress.org/support/topic/w3tc-0928-killed-my-backend
