Answers.Body: <p>The issue has to do with another third party plugin (<a href="https://github.com/objectivehtml/Postmaster-for-Craft-CMS" rel="nofollow noreferrer">Postmaster</a>) installed and also using <a href="http://carbon.nesbot.com" rel="nofollow noreferrer">Carbon</a>. The Postmaster plugin appears to be using an older copy of Carbon and Calendar is loading Postmaster's Carbon library, causing issues.</p>
  
  <p>Manually updating the <strong>vendors</strong> directory to use latest versions may resolve this issue. We will try to reach out to the developer of Postmaster and see if they can resolve this on their end. :)</p>
  
  <p>Customers effected with this issue can contact <a href="https://solspace.com/craft/create-ticket/calendar" rel="nofollow noreferrer">Solspace support</a> for an updated <strong>vendors</strong> folder for Postmaster that may resolve the issue.</p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2016-12-13T04:02:17.803Z
Answers.LastActivityDate: 2016-12-13T04:02:17.803Z
Answers.UserDisplayName: Solspace
Body: <p>I've got Solspace Calendar installed to the best of my knowledge. I have repurposed the 'calendar_demo' files to 'calendar'. Both /calendar and /calendar_demo just show:</p>
  
  <blockquote>
    <p>"Call to undefined method Calendar\Library\Carbon::setWeekStartsAt()" in DateHelper.php.</p>
  </blockquote>
  
  <p>/calendar/week does the same. A path like calendar/2016/11 just give a Twig error.</p>
  
  <p>I can't understand why this is happening. I'll give more details if you ask me, I don't know what else to give.</p>
  
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2016-11-09T18:54:27.180Z
Comments.Text: Have you tried contacting Solspace on the chance it's a bug?
Comments.UserDisplayName: Brad Bell
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2016-11-10T07:10:45.650Z
Comments.Text: Just to clarify, does this error happen when you use the demo templates (without modifying templates, paths, etc)?
Comments.UserDisplayName: Solspace
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2016-11-16T19:57:36.280Z
Comments.Text: @solspace. Yes, that is correct.
Comments.UserDisplayName: Lynsey Gwin
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2016-11-16T19:58:31.737Z
Comments.Text: I happens on my local and dev environments.
Comments.UserDisplayName: Lynsey Gwin
Tags: <plugin-solspacecalendar>
Title: "Call to undefined method Calendar\Library\Carbon::setWeekStartsAt()" Solspace Calendar
ThreadText: # "Call to undefined method Calendar\Library\Carbon::setWeekStartsAt()" Solspace Calendar
  
  (Asked by: username_0 on 2016-11-09)
  
  I've got username_2 Calendar installed to the best of my knowledge. I have repurposed the 'calendar\_demo' files to 'calendar'. Both /calendar and /calendar\_demo just show:
  
  > "Call to undefined method Calendar\Library\Carbon::setWeekStartsAt()" in DateHelper.php.
  
  /calendar/week does the same. A path like calendar/2016/11 just give a Twig error.
  
  I can't understand why this is happening. I'll give more details if you ask me, I don't know what else to give.
  
  **Tags:** plugin-solspacecalendar
  
  > **Comments:**
  > **username_1**: Have you tried contacting username_2 on the chance it's a bug?  
  > **username_2**: Just to clarify, does this error happen when you use the demo templates (without modifying templates, paths, etc)?  
  > **username_0**: @username_2. Yes, that is correct.  
  > **username_0**: I happens on my local and dev environments.  
  
  ---
  
  ## 1 answers
  
  ### Answer by username_2 on 2016-12-13. Score: 1
  
  The issue has to do with another third party plugin ([Postmaster](https://github.com/objectivehtml/Postmaster-for-Craft-CMS)) installed and also using [Carbon](http://carbon.nesbot.com). The Postmaster plugin appears to be using an older copy of Carbon and Calendar is loading Postmaster's Carbon library, causing issues.
  
  Manually updating the **vendors** directory to use latest versions may resolve this issue. We will try to reach out to the developer of Postmaster and see if they can resolve this on their end. :)
  
  Customers effected with this issue can contact [username_2 support](https://username_2.com/craft/create-ticket/calendar) for an updated **vendors** folder for Postmaster that may resolve the issue.
  
  
  ---
  
  