Getting errors while upgrading to Magento 1.8 version? Find the solutions to common Magento 1.8 Upgrade Issues and Errors.

1. Magento 1.8 Upgrade Errors with
Solutions
Error #1: No Reindex Product Price after Upgrading 1.6.1 > 1.8.1
Solution
Reindexing is one of the common Magento Upgrade errors which occurs due to changes
in Magento Database. If you are getting this issue then you can fix it with the help of
Magento database repair tool. This tool will help you comparing 2 databases
i.e. Corrupt and Target. By comparing both the database this repair tool will fix the
corrupt database. You can get the Magento Database repair tool from:
http://www.magentocommerce.com/download
Error #2: Customers cannot Login after upgrade to 1.8.1
Solution
Another very common error that Magento users get while upgrading their stores is their
customers unable to login to the store. Here is the solution to fix this issue:
Go to template/customer/form/login.phtml and
template/persistent/customer/form/login.phtml and under
Here is the solution:
1 – Go to template/customer/form/login.phtml and
template/persistent/customer/form/login.phtml and under
<ul class="form-list">
Add following code in login form
<input type="hidden" name="form_key" value="<?php echo
Mage::getSingleton('core/session')->getFormKey(); ?>" />

2. Error #3: Fatal error: Class ‘Mage_Googlecheckout_Helper_Data’ not found in
/app/Mage.php on line 547
Solution:
You canfix this replacing ...appcodecoreMageGoogleCheckoutetcconfig.xml file
with the ...appcodecoreMageGoogleCheckoutetcconfig.xml (old one). In short
don’t delete or replace your old config.xml file with new one.
Once you have place old config.xml file, clear the cache under System / Cache
Management.
Error #4: Categories tree not working adding a product after 1.8.1 upgrade
Solution:
This issue is related to database. So first of all take backup of your database and run
following SQL queries on DB.
UPDATE catalog_category_entity SET level = (SELECT LENGTH(path)-
LENGTH(REPLACE(path,'/','')) AS tmpl FROM (SELECT * FROM catalog_category_ent
ity) AS table1 WHERE catalog_category_entity.entity_id = table1.entity_id);
UPDATE catalog_category_entity SET children_count = (SELECT COUNT(*) FROM (SE
LECT * FROM catalog_cat
Error# 5: SQLSTATE[42S22]: Column not found: 1054 Unknown column
‘cpf.status’ in ‘where clause’
Solution:
Follow below mentioned steps to solve this issue:
a) Turn off all external extensions in your Magento Admin
b) Go to your app/etc/modules folder

3. c) Download the .xml files from the extensions you have, open these and edit the line
from <active>true</active> to <active>false</active> and upload the files again.
d) Clear cache, reindex from Magento Admin
Few more Magento 1.8 Upgrade Issues:
Error #6: 500 error after Magento 1.8 Upgrade
Error#7: Website is in Maintenance Mode even after upgrade
Error #8: Broken Product Images after Upgrade
Get solution to all these errors at:
http://www.softprodigy.com/blog/magento-1-8-upgrade-errors-with-solutions/