Mage registry key "_singleton/custom_export/Observer" already exists

Question

desperate here.. i was installing an extension through connect and i received the following message and now i have zero access.. could use your help.. thanks

Mage registry key "_singleton/custom_export/Observer" already exists

Trace:
#0 /var/www/html/evoraoralprobiotics/store/app/Mage.php(222): Mage::throwException('Mage registry k...')
#1 /var/www/html/evoraoralprobiotics/store/app/Mage.php(476): Mage::register('_singleton/cust...', false)
#2 /var/www/html/evoraoralprobiotics/store/app/code/core/Mage/Core/Model/App.php(1316): Mage::getSingleton('custom_export/O...')
#3 /var/www/html/evoraoralprobiotics/store/app/Mage.php(447): Mage_Core_Model_App->dispatchEvent('adminhtml_block...', Array)
#4 /var/www/html/evoraoralprobiotics/store/includes/src/Mage_Adminhtml_Block_Template.php(80): Mage::dispatchEvent('adminhtml_block...', Array)
#5 /var/www/html/evoraoralprobiotics/store/includes/src/__default.php(1794): Mage_Adminhtml_Block_Template->_toHtml()
#6 /var/www/html/evoraoralprobiotics/store/includes/src/Mage_Adminhtml_Block_Dashboard_Diagrams.php(55): Aitoc_Aitsys_Model_Rewriter_Mage_Core_Block_Abstract->toHtml()
#7 /var/www/html/evoraoralprobiotics/store/includes/src/__default.php(1169): Mage_Adminhtml_Block_Dashboard_Diagrams->_prepareLayout()
#8 /var/www/html/evoraoralprobiotics/store/includes/src/__default.php(42837): Aitoc_Aitsys_Model_Rewriter_Mage_Core_Block_Abstract->setLayout(Object(Aitoc_Aitsys_Model_Core_Layout))
#9 /var/www/html/evoraoralprobiotics/store/includes/src/Mage_Adminhtml_Block_Dashboard.php(66): Mage_Core_Model_Layout->createBlock('adminhtml/dashb...')
#10 /var/www/html/evoraoralprobiotics/store/includes/src/__default.php(1169): Mage_Adminhtml_Block_Dashboard->_prepareLayout()
#11 /var/www/html/evoraoralprobiotics/store/includes/src/__default.php(42837): Aitoc_Aitsys_Model_Rewriter_Mage_Core_Block_Abstract->setLayout(Object(Aitoc_Aitsys_Model_Core_Layout))
#12 /var/www/html/evoraoralprobiotics/store/includes/src/__default.php(42853): Mage_Core_Model_Layout->createBlock('adminhtml/dashb...', 'dashboard')
#13 /var/www/html/evoraoralprobiotics/store/includes/src/__default.php(42620): Mage_Core_Model_Layout->addBlock('adminhtml/dashb...', 'dashboard')
#14 /var/www/html/evoraoralprobiotics/store/includes/src/__default.php(42586): Mage_Core_Model_Layout->_generateBlock(Object(Mage_Core_Model_Layout_Element), Object(Mage_Core_Model_Layout_Element))
#15 /var/www/html/evoraoralprobiotics/store/includes/src/__default.php(42591): Mage_Core_Model_Layout->generateBlocks(Object(Mage_Core_Model_Layout_Element))
#16 /var/www/html/evoraoralprobiotics/store/includes/src/__default.php(3076): Mage_Core_Model_Layout->generateBlocks()
#17 /var/www/html/evoraoralprobiotics/store/includes/src/__default.php(3001): Mage_Core_Controller_Varien_Action->generateLayoutBlocks()
#18 /var/www/html/evoraoralprobiotics/store/includes/src/Mage_Adminhtml_Controller_Action.php(275): Mage_Core_Controller_Varien_Action->loadLayout(NULL, true, true)
#19 /var/www/html/evoraoralprobiotics/store/app/code/core/Mage/Adminhtml/controllers/DashboardController.php(40): Mage_Adminhtml_Controller_Action->loadLayout()
#20 /var/www/html/evoraoralprobiotics/store/includes/src/__default.php(3151): Mage_Adminhtml_DashboardController->indexAction()
#21 /var/www/html/evoraoralprobiotics/store/includes/src/__default.php(35033): Mage_Core_Controller_Varien_Action->dispatch('index')
#22 /var/www/html/evoraoralprobiotics/store/includes/src/__default.php(34590): Mage_Core_Controller_Varien_Router_Standard->match(Object(Mage_Core_Controller_Request_Http))
#23 /var/www/html/evoraoralprobiotics/store/app/code/core/Mage/Core/Model/App.php(354): Mage_Core_Controller_Varien_Front->dispatch()
#24 /var/www/html/evoraoralprobiotics/store/app/Mage.php(683): Mage_Core_Model_App->run(Array)
#25 /var/www/html/evoraoralprobiotics/store/index.php(88): Mage::run('', 'store')
#26 {main}

Standard practice before installing any modules is to disable the compiler and turn off all items in cache management. Sounds like cache corruption combined with module pre-install compiled code which isn't coexisting with the module. Clear cache and compiled code. — Fiasco Labs

Niraj C. Niraj C. · Accepted Answer · 2016-06-24T06:41:48

The same happened to me while uninstalling EasyPDF. There are dependent extensions that needs to be removed before installing the main extension itself. Once we get this error its hard to login to admin or go to connect manager again.

If you know which extension is causing it. Follow these steps:

Go to this link where you can download the compressed extension file that you can simply extract in your magento install directory to install it again.
You can then login to admin and then follow the instruction provided in their user guide to uninstall it properly.

Hope this helps in your case too.

Mage registry key "_singleton/custom_export/Observer" already exists

1 Answers