I had a customer update their Magento install and after got reports that chrome users couldn’t log in some times. I found a post that point me in the right direction after spreading a while researching the issue.
The trick was to create the directory app/code/local/Mage/Customer/Model and copy the file Session.php from app/code/core/Mage/Customer/Mode into it.
Then comment out $this->renewSession(); from the setCustomerAsLoggedIn Function.
So it looks like this.
public function setCustomerAsLoggedIn($customer)
Make sure to clear out all login cookies using ./n98-magerun.phar cache:clean config
If this doesn’t work try running n98-magerun.phar sys:check and check if there are any issues listed.