Magento - Mage registry key "_resource_helper/core" already exists

Question

I'm migrating a magento 1.6.1 installation on my staging server, but I'm still getting the error Mage registry key "_resource_helper/core" already exists.

I migrated the db and the whole source code. Then I changed local.xml database settings.

I already ran rm -rf var/cache/* var/session/* and restarted Apache2 but can't get it working.

What should I do?

Solution 1

I had this same problem. For me, this fixed it:

rm -rf /tmp/magento/var/cache/*

Solution 2

You need add this on local.xml:

<model><![CDATA[mysql4]]></model>

IF you already did this and error persist, you need clear your cache. Inside of your magento folder:

rm -rf var/cache/

or remove manually. ;)