I updated to Gravity Forms 1.8.8 this morning. When I reactivated I got an admin white screen of death.
This is not the first time this has happened, and it is related to this MailPoet Gravity Forms Add On plugin.
This plugin is a fussy little guy. I need it and it does work, however, this white screen of death for admin issue needs to be fixed.
If you get a white screen of death, ftp into your files and rename the plugins folder (something like "pluginsde").
This will deactivate all of your plugins and you will be able to get back into your wordpress admin.
Once in, go to the plugins screen and you will see error messages stating that your plugins cannot be found.
Go back to the file in ftp and restore the name to "plugins". Reload the plugins screen. All of your plugins will be there.
You can go ahead and reactivate everything EXCEPT FOR THE MAILPOET GRAVITY FORMS ADD ON.
After everything is reactivated and you have the latest version of Gravity forms updated....THEN AND ONLY THEN, REACTIVATE THE MAILPOET Gravity Forms plugin.
Everything should now work fine.
If not, repeat the above steps and activate everything except for the gravity forms plugin and any gravity forms addons.
Then activate the gravity forms plugin and related plugins one at a time, starting with the newly updated version of gravity forms.
Once again, DO NOT ACTIVATE the MailPoet Gravity Forms Add on until all of your other gravity forms related plugins are activated.