Trouble Upgrading from 2.5.5 to 2.8.1 - white screen

Question

I have been trying to upgrade a site from EE 2.5.5 to EE 2.8.1, but I get a white screen on the admin.php page after the upgrade is complete. The only way to get rid of the white screen is to disable extensions in the config.php file. I also get the login window that usually appears after the usual non-use timeout, except it is not a popup. This happens, when I am logged in. It appears at the bottom of the control panel - see screebshot below.

I have tried upgrading all plugins, but so far I cannot enable extensions without getting the white screen.

I have upgraded numerous sites to EE 2.8.1 but none have been this problematic. Any sage advice is welcome.

Thanks.

Answer 1

Have you checked all of your installed add-ons for updated versions? White screens are also typically a sign of hidden errors, so make sure that display_errors is enabled in your PHP environment, and set the $debug value in the admin.php file to 1. That may reveal a PHP error that identifies the problem.

If that doesn't help, and you think you have the latest versions of each add-on but it's still not working, as a last measure of debugging you could flip the enabled field for each entry in the exp_extensions table to n (after noting which are already y/n so that you can restore those values after testing). Then re-enable them one at a time by updating each row to y. When you run into the problem again, you've at least identified the offending add-on.