Title: Fatal error: Uncaught Error: Call to undefined function theme_data_setup()
Last modified: June 15, 2021

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# Fatal error: Uncaught Error: Call to undefined function theme_data_setup()

 *  Resolved [tecnowp](https://wordpress.org/support/users/tecnowp/)
 * (@tecnowp)
 * [4 years, 10 months ago](https://wordpress.org/support/topic/fatal-error-uncaught-error-call-to-undefined-function-theme_data_setup/)
 * Hello,
    i just upgraded to last Wallstreet (Light) theme and I get the error “
   Fatal error: Uncaught Error: Call to undefined function theme_data_setup()” in
   header.php on my staging site. I’m actualy running a child theme using Wallstreet
   as parent theme. Could you help me with this? Thank you
 * The page I need help with: _[[log in](https://login.wordpress.org/?redirect_to=https%3A%2F%2Fwordpress.org%2Fsupport%2Ftopic%2Ffatal-error-uncaught-error-call-to-undefined-function-theme_data_setup%2F%3Foutput_format%3Dmd&locale=en_US)
   to see the link]_

Viewing 4 replies - 1 through 4 (of 4 total)

 *  [akhlesh-nagar](https://wordpress.org/support/users/akhlesh-nagar/)
 * (@akhlesh-nagar)
 * [4 years, 10 months ago](https://wordpress.org/support/topic/fatal-error-uncaught-error-call-to-undefined-function-theme_data_setup/#post-14557646)
 * Hi
    Thanks for contacting to us. Let me know clear, Have you crated new child
   theme of Wallstreet theme or using one of our [existing child](https://wordpress.org/themes/search/wallstreet/)
   theme. Pls clear us so that we can assist you better.
 * Thanks
    Akhilesh
 *  Thread Starter [tecnowp](https://wordpress.org/support/users/tecnowp/)
 * (@tecnowp)
 * [4 years, 10 months ago](https://wordpress.org/support/topic/fatal-error-uncaught-error-call-to-undefined-function-theme_data_setup/#post-14557703)
 * Hello, thank you for coming back to me. I created my own child theme. Infact 
   at the moment I’m checking the files I added at that time
 *  Thread Starter [tecnowp](https://wordpress.org/support/users/tecnowp/)
 * (@tecnowp)
 * [4 years, 10 months ago](https://wordpress.org/support/topic/fatal-error-uncaught-error-call-to-undefined-function-theme_data_setup/#post-14557784)
 * Infact I creasted a new header file in my child theme, I’m sure the conflict 
   is there…
 *  [akhlesh-nagar](https://wordpress.org/support/users/akhlesh-nagar/)
 * (@akhlesh-nagar)
 * [4 years, 10 months ago](https://wordpress.org/support/topic/fatal-error-uncaught-error-call-to-undefined-function-theme_data_setup/#post-14557942)
 * HI
    If you didn’t added your customized code in header.php file of child theme
   you can delete the file.
 * Thanks
    Akhilesh

Viewing 4 replies - 1 through 4 (of 4 total)

The topic ‘Fatal error: Uncaught Error: Call to undefined function theme_data_setup()’
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   png)
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 * 4 replies
 * 2 participants
 * Last reply from: [akhlesh-nagar](https://wordpress.org/support/users/akhlesh-nagar/)
 * Last activity: [4 years, 10 months ago](https://wordpress.org/support/topic/fatal-error-uncaught-error-call-to-undefined-function-theme_data_setup/#post-14557942)
 * Status: resolved