Answers.Body: <p>Ran into something similar. There are some database table alteration between 4.7.5 and 4.7.6 (specifically relating to foreign keys). These edited CiviMail tables. If you have used CiviMail extensively, these tables could be quite large. The <code>ALTER TABLE</code> commands can take a very long time causing time outs. </p>
  
  <p>The quickest option is to backup these tables, trucate them, run the CiviCRM 4.7.5 to 4.7.6 upgrade comands, and, finally, reimport the data.</p>
  
  <p><strong>Affected tables:</strong></p>
  
  <ul>
  <li><code>civicrm_mailing_event_queue</code></li>
  <li><code>civicrm_mailing_recipients</code></li>
  </ul>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2016-04-21T15:32:54.870Z
Answers.Text: I've never been able to get CiviCRM running on this site so these tables have not been used. I have not sent out any CiviMail
Answers.UserDisplayName: Vietyank
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2016-04-23T03:56:36.383Z
Answers.Text: I tried the steps above by setting the foreign_key_checks = 0 then truncated the tables and setting the checks back to 1. This did not help. I still got the error page when I ran the upgrade script
Answers.UserDisplayName: Vietyank
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2016-04-23T04:55:20.547Z
Answers.Text: I am going to start all over again. I have deleted the civicrm files and will attempt a fresh install
Answers.UserDisplayName: Vietyank
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2016-04-21T08:14:00.793Z
Answers.LastActivityDate: 2016-04-21T08:14:00.793Z
Answers.UserDisplayName: David Hayes
Answers.Body: <p>Same thing with Joomla but this is a database issue, not website platform. Seems there is an error with a FOREIGN_KEY_CHECK or field during 4.7.5 schema update. See screenshot.</p>
  
  <p><a href="https://i.sstatic.net/y0Mv4.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/y0Mv4.jpg" alt="enter image description here"></a></p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2016-04-22T00:49:40.197Z
Answers.LastActivityDate: 2016-04-22T00:49:40.197Z
Answers.UserDisplayName: BruceW
Answers.Body: <p>This question is a duplicate of <a href="https://civicrm.stackexchange.com/questions/11522/upgrade-fails-4-7-4-4-7-6-in-wp-4-5-1">Upgrade Fails 4.7.4 - 4.7.6 in WP 4.5.1</a>.  This question was asked first, but it couldn't be diagnosed.  The original poster's theme and/or PHP settings are suppressing error output that others like @BruceW had.</p>
  
  <p>I'm going to say that the answer to this question is "use the default theme when troubleshooting upgrade issues" and <a href="http://php.net/manual/en/function.error-reporting.php" rel="nofollow noreferrer">turn PHP error reporting to maximum</a>.  I'll answer the actual issue on the other question, since that one is more likely to be found by others.</p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2016-05-10T02:45:02.347Z
Answers.LastActivityDate: 2016-05-10T02:45:02.347Z
Answers.LastEditDate: 2017-04-13T12:53:13.017Z
Answers.UserDisplayName: Jon G - Megaphone Tech
Body: <p>Wordpress 4.5
  CiviCRM 4.7.6</p>
  
  <p>I have installed the CiviCRM 4.7.6 plugin and get a message that I need to upgrade the database. When I try the upgrade, get a white screen displayed with the single word "error" in the upper left. Then I cannot access any Wordpress functions and have to reload the datbase again.</p>
  
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2016-04-21T04:18:31.677Z
Comments.Text: If you check the log files (usually in <wordpressroot>/wp-content/plugins/files/civicrm/ConfigAndLog) do you see any more info about the error?
Comments.UserDisplayName: Jon G - Megaphone Tech
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2016-04-21T07:11:23.363Z
Comments.Text: There is no such  directory, civicrm, in that path
Comments.UserDisplayName: Vietyank
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2016-04-21T15:21:17.113Z
Comments.Text: Search your file system for the ConfigAndLog directory, it's there somewhere!
Comments.UserDisplayName: Jon G - Megaphone Tech
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2016-04-21T15:31:46.413Z
Comments.Text: Nope...it doesn't exist
Comments.UserDisplayName: Vietyank
Tags: <wordpress><upgrade>
Title: Unable to upgrade to 4.7.6
ThreadText: # Unable to upgrade to 4.7.6
  
  (Asked by: username_0 on 2016-04-20)
  
  Wordpress 4.5
  CiviCRM 4.7.6
  
  I have installed the CiviCRM 4.7.6 plugin and get a message that I need to upgrade the database. When I try the upgrade, get a white screen displayed with the single word "error" in the upper left. Then I cannot access any Wordpress functions and have to reload the datbase again.
  
  **Tags:** wordpress, upgrade
  
  > **Comments:**
  > **username_1**: If you check the log files (usually in <wordpressroot>/wp-content/plugins/files/civicrm/ConfigAndLog) do you see any more info about the error?  
  > **username_0**: There is no such  directory, civicrm, in that path  
  > **username_1**: Search your file system for the ConfigAndLog directory, it's there somewhere!  
  > **username_0**: Nope...it doesn't exist  
  
  ---
  
  ## 3 answers
  
  ### Answer by username_2 on 2016-04-21. Score: 2
  
  Ran into something similar. There are some database table alteration between 4.7.5 and 4.7.6 (specifically relating to foreign keys). These edited CiviMail tables. If you have used CiviMail extensively, these tables could be quite large. The `ALTER TABLE` commands can take a very long time causing time outs.
  
  The quickest option is to backup these tables, trucate them, run the CiviCRM 4.7.5 to 4.7.6 upgrade comands, and, finally, reimport the data.
  
  **Affected tables:**
  
  * `civicrm_mailing_event_queue`
  * `civicrm_mailing_recipients`
  
  > **Comments:**
  > **username_0**: I've never been able to get CiviCRM running on this site so these tables have not been used. I have not sent out any CiviMail  
  > **username_0**: I tried the steps above by setting the foreign_key_checks = 0 then truncated the tables and setting the checks back to 1. This did not help. I still got the error page when I ran the upgrade script  
  > **username_0**: I am going to start all over again. I have deleted the civicrm files and will attempt a fresh install  
  
  ---
  
  ### Answer by username_3 on 2016-04-22. Score: 1
  
  Same thing with Joomla but this is a database issue, not website platform. Seems there is an error with a FOREIGN\_KEY\_CHECK or field during 4.7.5 schema update. See screenshot.
  
  [![enter image description here](https://i.sstatic.net/y0Mv4.jpg)](https://i.sstatic.net/y0Mv4.jpg)
  
  
  ---
  
  ### Answer by username_1 on 2016-05-10. Score: 1
  
  This question is a duplicate of [Upgrade Fails 4.7.4 - 4.7.6 in WP 4.5.1](https://civicrm.stackexchange.com/questions/11522/upgrade-fails-4-7-4-4-7-6-in-wp-4-5-1). This question was asked first, but it couldn't be diagnosed. The original poster's theme and/or PHP settings are suppressing error output that others like @username_3 had.
  
  I'm going to say that the answer to this question is "use the default theme when troubleshooting upgrade issues" and [turn PHP error reporting to maximum](http://php.net/manual/en/function.error-reporting.php). I'll answer the actual issue on the other question, since that one is more likely to be found by others.
  
  
  ---
  
  