Mage registry key "_singleton/massemail/observer" already exists can't login to admin panel

[bestcurls]

Hello~ I'm new to magento need help plz error pop up admin panel cant login in

i was doing cache flush magento , flush cache storage 2 more additional cache it was status ( Disabled) to (enable) and last Compilation (Enable) to ( Disabled)

Mage registry key "_singleton/massemail/observer" already exists

Trace:
#0 /chroot/home/bestcurl/bestcurls.com/html/app/Mage.php(222): Mage::throwException('Mage registry k...')
#1 /chroot/home/bestcurl/bestcurls.com/html/app/Mage.php(476): Mage::register('_singleton/mass...', false)
#2 /chroot/home/bestcurl/bestcurls.com/html/includes/src/__default.php(21023): Mage::getSingleton('massemail/obser...')
#3 /chroot/home/bestcurl/bestcurls.com/html/app/Mage.php(447): Mage_Core_Model_App->dispatchEvent('core_block_abst...', Array)
#4 /chroot/home/bestcurl/bestcurls.com/html/includes/src/__default.php(1892): Mage::dispatchEvent('core_block_abst...', Array)
#5 /chroot/home/bestcurl/bestcurls.com/html/includes/src/__default.php(27294): Mage_Core_Block_Abstract->setLayout(Object(Mage_Core_Model_Layout))
#6 /chroot/home/bestcurl/bestcurls.com/html/includes/src/__default.php(27310): Mage_Core_Model_Layout->createBlock('adminhtml/page_...', 'head')
#7 /chroot/home/bestcurl/bestcurls.com/html/includes/src/__default.php(27077): Mage_Core_Model_Layout->addBlock('adminhtml/page_...', 'head')
#8 /chroot/home/bestcurl/bestcurls.com/html/includes/src/__default.php(27043): Mage_Core_Model_Layout->_generateBlock(Object(Mage_Core_Model_Layout_Element), Object(Mage_Core_Model_Layout_Element))
#9 /chroot/home/bestcurl/bestcurls.com/html/includes/src/__default.php(27044): Mage_Core_Model_Layout->generateBlocks(Object(Mage_Core_Model_Layout_Element))
#10 /chroot/home/bestcurl/bestcurls.com/html/includes/src/__default.php(13507): Mage_Core_Model_Layout->generateBlocks()
#11 /chroot/home/bestcurl/bestcurls.com/html/includes/src/__default.php(13432): Mage_Core_Controller_Varien_Action->generateLayoutBlocks()
#12 /chroot/home/bestcurl/bestcurls.com/html/includes/src/Mage_Adminhtml_Controller_Action.php(275): Mage_Core_Controller_Varien_Action->loadLayout(NULL, true, true)
#13 /chroot/home/bestcurl/bestcurls.com/html/app/code/core/Mage/Adminhtml/controllers/DashboardController.php(40): Mage_Adminhtml_Controller_Action->loadLayout()
#14 /chroot/home/bestcurl/bestcurls.com/html/includes/src/__default.php(13582): Mage_Adminhtml_DashboardController->indexAction()
#15 /chroot/home/bestcurl/bestcurls.com/html/includes/src/__default.php(17927): Mage_Core_Controller_Varien_Action->dispatch('index')
#16 /chroot/home/bestcurl/bestcurls.com/html/includes/src/__default.php(17484): Mage_Core_Controller_Varien_Router_Standard->match(Object(Mage_Core_Controller_Request_Http))
#17 /chroot/home/bestcurl/bestcurls.com/html/includes/src/__default.php(20061): Mage_Core_Controller_Varien_Front->dispatch()
#18 /chroot/home/bestcurl/bestcurls.com/html/app/Mage.php(683): Mage_Core_Model_App->run(Array)
#19 /chroot/home/bestcurl/bestcurls.com/html/index.php(87): Mage::run('', 'store')
#20 {main}

[Damian Culotta]

Hi @bestcurls,

Can you try to disable the compiler?

I think the easier way is using Magento shell.

Go to the shell directory and then run:

php compiler.php state

Now you'll see the current status of or compiler. If is enabled and/or compiled, please, execute this commands:

php compiler.php disable
php compiler.php clear

Now is disabled and you've cleared all the generated files.

[bestcurls]

Thank you so much for helping me

Some reason cant find compiler.php file shell

Thank you

[Damian Culotta]

@bestcurls,

My solution requires to connect by ssh to your server.

The file is located on /pat/to/magento/shell/compiler.php

[varunpv]

Hi,

The following solution has fixed the error for me

includes/src/__default.php(27077)

The error shows that the compiler hasn't disabled properly. So you need to enable the compiler and disable it again. Please run the following code from your SSH for the same. 

sudo php -f shell/compiler.php -- enable
sudo php -f shell/compiler.php -- disable
sudo php -f shell/compiler.php -- clear
sudo rm -rf var/cache/*
sudo var/session/*