Answers.Body: <p>I was having a similar issue and found a solution that worked for my setup:  <a href="https://craftcms.stackexchange.com/a/9016/831">https://craftcms.stackexchange.com/a/9016/831</a></p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2015-04-03T17:41:58.740Z
Answers.LastActivityDate: 2015-04-03T17:41:58.740Z
Answers.LastEditDate: 2017-04-13T12:51:00.253Z
Answers.UserDisplayName: Aaron Berkowitz
Answers.Body: <blockquote>
    <p>Cannot modify header information - headers already sent</p>
  </blockquote>
  
  <p>That error means that something, somewhere has already started outputting to the browser before Yii/Craft/PHP expected it to happen.</p>
  
  <p>99% of the time, it's some whitespace or unintended character that got added to the beginning of one of Craft's files.</p>
  
  <p>Try doing a fresh upload of all of Craft's files and see if that helps.</p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2015-02-25T21:07:01.473Z
Answers.Text: Hi Brad, thanks a lot for your answer. I already tried a completely fresh install in a new folder with a fresh db etc. The only files I touched were the craft/config/db.php and the public .htaccess for the standard index.php rewrite. Any other suggestions? Maybe it's an encoding issue?
Answers.UserDisplayName: Matthias Ott
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2015-02-25T21:14:52.677Z
Answers.Text: If you enable devMode, does any other helpful information get logged?
Answers.UserDisplayName: Brad Bell
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2015-02-26T16:06:13.467Z
Answers.Text: DevMode did not show anything of help – as far as I can tell. The only thing that worked was setting _display_errors_ to _Off_ in php.ini. Not my preferred solution, but it works for now…
Answers.UserDisplayName: Matthias Ott
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2015-02-25T15:36:51.637Z
Answers.LastActivityDate: 2015-02-25T15:36:51.637Z
Answers.UserDisplayName: Brad Bell
Body: <p>After a fresh install of Craft on my localhost, two problems occur:</p>
  
  <p>1) The modal window to upgrade Craft only says <em>"An unknown error occured."</em></p>
  
  <p>2) <strong>Newly created singles are not editable</strong>, the edit pane stays empty with no input fields at all.</p>
  
  <p>I looked into craft.log and there seems to be an issue with CHttpRequest.php, but I can't say if this is a local config problem or if it's a bug:</p>
  
  <pre><code>******************************************************************************************************
  2015/02/25 13:08:35 [error] [php] Cannot modify header information - headers already sent (/Users/me/Sites/test-dev-craft/app/framework/web/CHttpRequest.php:1392)
  Stack trace:
  #0 /Users/me/Sites/test-dev-craft/app/framework/web/CHttpRequest.php(1329): Craft\CookieCollection-&gt;remove()
  #1 /Users/me/Sites/test-dev-craft/app/services/UserSessionService.php(1170): Craft\CookieCollection-&gt;add()
  #2 /Users/me/Sites/test-dev-craft/app/framework/web/auth/CWebUser.php(203): Craft\UserSessionService-&gt;renewCookie()
  #3 /Users/me/Sites/test-dev-craft/app/services/UserSessionService.php(91): Craft\UserSessionService-&gt;init()
  #4 /Users/me/Sites/test-dev-craft/app/framework/base/CModule.php(387): Craft\UserSessionService-&gt;init()
  #5 /Users/me/Sites/test-dev-craft/app/etc/web/WebApp.php(569): Craft\WebApp-&gt;getComponent()
  #6 /Users/me/Sites/test-dev-craft/app/framework/base/CModule.php(103): Craft\WebApp-&gt;getComponent()
  #7 /Users/me/Sites/test-dev-craft/app/etc/web/WebApp.php(160): Craft\WebApp-&gt;__get()
  #8 /Users/me/Sites/test-dev-craft/app/framework/base/CApplication.php(180): Craft\WebApp-&gt;processRequest()
  #9 /Users/me/Sites/test-dev-craft/app/index.php(62): Craft\WebApp-&gt;run()
  #10 /Users/me/Sites/test.dev/index.php(19): require_once()
  REQUEST_URI=/test.dev/index.php/admin/actions/tasks/getRunningTaskInfo
  </code></pre>
  
  <p>This is my local setup:</p>
  
  <ul>
  <li>Mac OS X 10.10.2</li>
  <li>Apache/2.2.29 (Unix) DAV/2 mod_fastcgi/2.4.6 mod_ssl/2.2.29 OpenSSL/1.0.2</li>
  <li>PHP Version 5.6.5</li>
  <li>MySQL 5.6.22 - Homebrew</li>
  </ul>
  
  <p>Any help would be highly appreciated!</p>
  
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2015-03-05T23:23:01.017Z
Comments.Text: I've also had this problem, running from localhost. Mac OS X 10.10.3
  PHP 5.6.1
  Mysql 5.5.38
Comments.UserDisplayName: Chase Giunta
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2015-03-09T23:30:19.083Z
Comments.Text: I'm getting this error locally too. PHP 5.6
Comments.UserDisplayName: Seán O'Grady
Tags: <entries><control-panel><error><upgrades>
Title: Content / fields of newly created single don't show up
ThreadText: # Content / fields of newly created single don't show up
  
  (Asked by: username_0 on 2015-02-25)
  
  After a fresh install of Craft on my localhost, two problems occur:
  
  1) The modal window to upgrade Craft only says *"An unknown error occured."*
  
  2) **Newly created singles are not editable**, the edit pane stays empty with no input fields at all.
  
  I looked into craft.log and there seems to be an issue with CHttpRequest.php, but I can't say if this is a local config problem or if it's a bug:
  
  ```
  ******************************************************************************************************
  2015/02/25 13:08:35 [error] [php] Cannot modify header information - headers already sent (/Users/me/Sites/test-dev-craft/app/framework/web/CHttpRequest.php:1392)
  Stack trace:
  #0 /Users/me/Sites/test-dev-craft/app/framework/web/CHttpRequest.php(1329): Craft\CookieCollection->remove()
  #1 /Users/me/Sites/test-dev-craft/app/services/UserSessionService.php(1170): Craft\CookieCollection->add()
  #2 /Users/me/Sites/test-dev-craft/app/framework/web/auth/CWebUser.php(203): Craft\UserSessionService->renewCookie()
  #3 /Users/me/Sites/test-dev-craft/app/services/UserSessionService.php(91): Craft\UserSessionService->init()
  #4 /Users/me/Sites/test-dev-craft/app/framework/base/CModule.php(387): Craft\UserSessionService->init()
  #5 /Users/me/Sites/test-dev-craft/app/etc/web/WebApp.php(569): Craft\WebApp->getComponent()
  #6 /Users/me/Sites/test-dev-craft/app/framework/base/CModule.php(103): Craft\WebApp->getComponent()
  #7 /Users/me/Sites/test-dev-craft/app/etc/web/WebApp.php(160): Craft\WebApp->__get()
  #8 /Users/me/Sites/test-dev-craft/app/framework/base/CApplication.php(180): Craft\WebApp->processRequest()
  #9 /Users/me/Sites/test-dev-craft/app/index.php(62): Craft\WebApp->run()
  #10 /Users/me/Sites/test.dev/index.php(19): require_once()
  REQUEST_URI=/test.dev/index.php/admin/actions/tasks/getRunningTaskInfo
  
  ```
  
  This is my local setup:
  
  * Mac OS X 10.10.2
  * Apache/2.2.29 (Unix) DAV/2 mod\_fastcgi/2.4.6 mod\_ssl/2.2.29 OpenSSL/1.0.2
  * PHP Version 5.6.5
  * MySQL 5.6.22 - Homebrew
  
  Any help would be highly appreciated!
  
  **Tags:** entries, control-panel, error, upgrades
  
  > **Comments:**
  > **username_1**: I've also had this problem, running from localhost. Mac OS X 10.10.3 PHP 5.6.1 Mysql 5.5.38  
  > **username_2**: I'm getting this error locally too. PHP 5.6  
  
  ---
  
  ## 2 answers
  
  ### Answer by username_3 on 2015-04-03. Score: 2
  
  I was having a similar issue and found a solution that worked for my setup: <https://craftcms.stackexchange.com/a/9016/831>
  
  
  ---
  
  ### Answer by username_4 on 2015-02-25. Score: 0
  
  > Cannot modify header information - headers already sent
  
  That error means that something, somewhere has already started outputting to the browser before Yii/Craft/PHP expected it to happen.
  
  99% of the time, it's some whitespace or unintended character that got added to the beginning of one of Craft's files.
  
  Try doing a fresh upload of all of Craft's files and see if that helps.
  
  > **Comments:**
  > **username_0**: Hi username_4, thanks a lot for your answer. I already tried a completely fresh install in a new folder with a fresh db etc. The only files I touched were the craft/config/db.php and the public .htaccess for the standard index.php rewrite. Any other suggestions? Maybe it's an encoding issue?  
  > **username_4**: If you enable devMode, does any other helpful information get logged?  
  > **username_0**: DevMode did not show anything of help – as far as I can tell. The only thing that worked was setting _display_errors_ to _Off_ in php.ini. Not my preferred solution, but it works for now…  
  
  ---
  
  