I did an upgrade from 1.5 to 1.9 but after the upgrade I get the following error:

Fatal error: Call to undefined method Mage_Core_Model_App::getIsCacheLocked() in /var/www/demanchetknopenwinkel/app/code/core/Mage/Core/Model/Resource.php on line 112

I followed the steps from the site duntuk.com to upgrade but after that, no go.

Reindexing also gives the same problem.

Any idea on how to fix?



  • Have any app/code/local/Mage/ items? Nov 20, 2015 at 22:01
  • Yes I do. I have 4 items, Catalog, Checkout, Core and Sales. Nov 20, 2015 at 22:33

1 Answer 1


If you create class overwrites by copying the PHP file out of app/code/core/Mage to app/code/local/Mage and modifying the file, you must on upgrade take the modifications made to the 1.5 classes and apply it to the 1.9 code and replace the contents of app/code/local/Mage with that.

Code overwrites to core by copying the appropriate file to app/code/local/Mage include all the function blocks in that class, not just the modified function block and you end up with 1.9 trying to run with 1.5 classes. In this case, one of the local files is probably missing a method introduced with 1.9.

Creating a module that overwrites just the function block you want to modify tends to be cleaner, you have a lot less code to wade through and compare on upgrade.

  • After much testing I discussed the situation with my customer and we decided to build a new webshop in Magento Thanks for thinking with me anyway. Cheers to all Jan 19, 2016 at 21:46

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