I have a few Magento shops which gets this error after installing the Supee 8788 Patch. I cannot find anyone who have the same problem on Google...

Fatal error: Class 'Mage_Uploader_Helper_Data' not found in /www/app/Mage.php on line 547

Questions What could be causing this? Isn't there a way to see the stacktrace to see where it's called from?

1 Answer 1


Pretty sure it's caused by the fact that the patch was not installed properly.

The patch adds a new file app/code/core/Mage/Uploader/Helper/Data.php which matches the Mage_Uploader_Helper_Data class.

First, ensure that file is present.

If it's not present, that means the patch did not work.

If it's present, I suggest you flush the cache and recompile (if you have compilation enabled)

  • It was the compilation that caused the error. Thanks!! Commented Oct 18, 2016 at 9:37
  • 2
    In my case, compilation was disabled prior to installing the patch and afterwards I couldn't get into the admin panel at all. Recompiling via the CLI as described in this answer magento.stackexchange.com/questions/68010/… solved the problem for me. Commented Oct 18, 2016 at 19:43

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