I started the process of upgrading magento from 1.8 to 126.96.36.199 and I used downloader for this it.
At the end of the process I saw this error :
ONNECT ERROR: Failed to open file /home/unitedbro/public_html/downloader/.cache/community/Interface_Adminhtml_Default-188.8.131.52/app/design/adminhtml/default/default/template/downloadable/sales/order/invoice/create/items/renderer
Failed to open file /home/unitedbro/public_html/downloader/.cache/community/Interface_Frontend_Rwd_Default-184.108.40.206/app/design/frontend/rwd/default/template/configurableswatches/catalog/product/view/type/options/conf
and I see this error in error_log :
[26-Jun-2017 16:03:06 UTC] PHP Fatal error: Call to a member function isLockExists() on a non-object in /home/unitedbro/public_html/app/code/core/Mage/Index/Model/Lock.php on line 257
I tried clearing cache but it didn't help.
Hi, if you are unable to get the downloader to work, you could try downloading 220.127.116.11 manually from magento.com and moving the files into place instead. You will need to ensure that you don't delete folders/files from customisations that you need to keep.