Upgrade WordPress Got Trouble Admin Blank Page

Published on Monday, June 27, 2011
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This article was published on our brother website: GoGoToTo.com, We copied it to here because we think it is very important for most of WordPress site owners.

We tried to upgrade a WordPress site from 2.8.x (maybe 2.8.4) to 3.1.3 with upgrade automatically.

Before we upgrade, we have deactivate all plugins. But after we click “upgrade automatically”, first we got a error message screen:

"Briefly unavailable for scheduled maintenance. Check back in a minute."

After some while, we found our site can be visited without problem, but when we try to login Admin, the Admin show a complete blank page.

wpUpgradefail00_0

We searched related information in the internet, most of cases indicates the temporary file named .maintenance in the blog base folder, if you delete this file, your blog should be ok then.

Note: You have to make sure your FTP tool allows display hidden files, otherwise you can not see the .maintenance file.

Just check WordPress official help information about this:

How to clear the "Briefly unavailable for scheduled maintenance" message after doing automatic upgrade?

As part of the automatic upgrade WordPress places a file named .maintenance in the blog base folder (folder that contains the wp-admin folder). If that file exists, then vistors will see the message Briefly unavailable for scheduled maintenance. Check back in a minute.

To stop that message from being displayed to vistors, just delete the .maintenance file. The automatic upgrade should be executed again, just in case it failed.

However, for our case,** we did not need to remove .maintenance file**, and the site could be visited ok after short while. But the new problem was: The Admin page became a blank page.

Then we searched info about Admin blank page and spent long time, we tried all solutions which we could find, for example:

1: Deactivate all plugins without admin login, please followed WordPress help information like the following:

_via FTP_
  
_Create an empty plugins folder      
Via FTP or your host's control panel, navigate to the wp-contents folder (directory)       
Via FTP or your host's control panel, rename the folder "plugins" to "plugins.hold"       
Via FTP or your host's control panel, create new folder called "plugins"       
Login to your WordPress administration menus       
Via FTP or your host's control panel, delete the empty "plugins" you previous created       
Via FTP or your host's control panel, rename "plugins.hold" back to "plugins"_

2: Remove extra space at the end of wp-config file, and also at the beginning of the file;

3: Remove extra space at the end and beginning of a file named “functions.php”. the file located in theme folder, some people said located in wp-includes folder.

But anyway, what ever we changed which files, we still ONLY got an blank Admin page.

4: Later we found a case from internet: If want to deactivate all plugins, sometimes IT DOESN’T WORK if only change plugins folder name, but** need to change database:**

Then we go back to WordPress help information here and choose the “phpMyAdmin” way. wen to our site’s online database control panel, and use phpMyAdmin to change data in datatable wp_options table.

However, we found the data in the column option_value field has been already "a:0:", which means no plugin activated now. Because before we started to upgrade, we have already deactivated all plugins that we have installed.

So, our case is really different with above all cases, and different with most of cases which descripted in internet.

So what’s wrong with our WordPress site?

Finally we found our solution and upgraded successfully ! please read the procedure which we did:

We think since our site still can be visited without any problem, and we have known all known solutions in internet are different with our case. so we’d better think about the exact reason for our case;

Our site could be visited all the time but only admin was not correct, so we thought why we did not just replace Admin folder with backup folder ? (so now you know the backup is so important before you upgrade your WordPress site).

1: Then we change the wp-admin foler name to wp-admin_bak, use FTP tool to upload our backup wp-admin folder to online site.

Bingo! now we found our Admin can be accessed and can be logged in ! and also our site still visit correctly.

2: The dashboard still show the 2.8.4 version and gives information to upgrade. And also we made sure all plugins were deactivated.

But, this time we did another thing:** we changed theme to default theme which WordPress provided**. Not sure this step is required or not. but we just did it.

3: We used automatically upgraded again. … But, We still got the same error:

"Briefly unavailable for scheduled maintenance. Check back in a minute."

4: OK, we did not have other choice, since it asked that we should at least wait a minute, then why we do not wait? Then we left away to read news, to watch TV …

5: About 30 minutes later we came back, the error screen was still there, when we tried to refresh screen, it asked if refresh, something might have be restarted, but we were using Chrome browser, we think the prompt message should be from Chrome browser. Then we changed the URL in browser to www.oursitesdomain.com/wp-admin and click enter key…

7: Bingo! Now we got another message (no more a blank screen !! ) which indicated the upgraded process did not upgrade database successfully (or completely, we can not remember exact message.) Do you want to upgrade database ?

Yes, sure! We selected upgrading database automatically.

8: Then finally we got a dashboard screen like the following:

wpUpgradefail00

You can see the WordPress version is already the newest version, but just there was a message on the top indicated: An automated WordPress update has failed to complete, please attempt the update again now. We then clicked the update again now link. Then everything showing OK finally.

We got our site back. This is our case, it is really different with most of known case in the internet. We were lucky.

Let us remind you again:** DO backup files and database before you upgrade anything** !