Upgrade 1.3.8 -> 1.3.9b gives a blank page on admin

Hello,

I just upgraded my web site from 1.3.8 -> 1.3.9b. Upgrade went smoothly, but after finishing the process with the database upgrade, I get a blank page on the admin site...

• The customer site is working fine
• There is no error log saved in the cache folder
• I re-checked all modifications a second time, and re-uploaded all files of the admin folder, without success
• The 2 configure.php files are fine

With just a blank page, it is really difficult to understand where the error is coming from. How should I start?

The FAQ area is a good place to start: https://www.zen-cart.com/tutorials/index.php?article=82

I of course already checked that FAQ :

• As I said, I already re-uploaded several times (3 to be precise) all the files, without any change

• I use WinMerge to update my modified files, and did twice the whole process - since it did not work the first time, I thought I might have made a mistake, and started again from scrach, without any sucess

• "Common customization errors", this is really vague... Why don't I get any error message ? I can deal with an error message, but how on earth is it possible to get just a blank page? This doesn't really make sens to me, my files are not empty, I should get something on the screen...

It should be showing you all your PHP errors in the log files. They intentionally never show to the screen, because that would create security problems.

But maybe something in your upgrade has damaged one or more of the bootstrap files that load before the debug logger is enabled, in which case you'll have to take much more drastic measures to find your problems:

Near the top of your /admin/includes/application_top.php file, you'll see this line:```
define('DEBUG_AUTOLOAD', false);

Change that false to true, and add another line directly below it, as shown here:```
define('DEBUG_AUTOLOAD', [B]true[/B]);
[B]define('STRICT_ERROR_REPORTING', true);[/B]

Now you should see all kinds of information, including errors and warnings and headers-already-sent messages, etc. Many of those messages will be a result of earlier messages, and thus not all information is actually indicative of an "error", so be careful not to send yourself on a wild goose chase.

What addons do you have installed?

I added this line, and still no error message whatsoever...

By installing the original 1.3.9 admin files OR my backup 1.3.8 admin files, everything is working fine. However, when I place my new 1.3.9 files, I get this blank screen. This means that my edits must be faulty.

I have quite a lot of add-ons, including super_orders, edit_orders, green tea, profit_margin_calculator, login_as_customer, add_customers_from_admin, birthday, sales_Report... Plenty of possibilities to make mistakes! What surprises me is that I always made my upgrades without (too much) troubles, until this time...

I get this same blank page in admin after upgrading. I have also re uploaded the files a number of times and get no admin error messages in the Cache folder.

What I have notice though after I log into Admin, from the blank page I can access admin by pointing my browser to it?

So ... it lets you login if you point your browser to it. Um ... that's what one would expect. How can you login if you don't point your browser to it?

After logging in on the login.php page I just get a blank page with the address admin/login.php?zenAdminID=xxxxxxx, then when I browse to admin/ I get access to admin and it works fine.

I have re uploaded the files a number of times and get no admin error messages in the Cache folder. I have added the lines of code that you suggested in an earlier post with no apparent error messages

What exactly are all the differences between your admin files and the clean admin files of the original unzipped Zen Cart files?
You're encountering an error as a result of something failing ... and a clean install doesn't fail, so you've either got something "extra" or something "missing".

Thanks Dr Byte For helping me, I was only looking in the admin folder for the problem when it lay with meta_tags.php

Cheers