I did an upgrade from Magento CE 188.8.131.52 --> 1.9.1 in my staging environment The frontend is just working fine but the backend gives me the headache. * I can't login. It only shows a white screen and no errors.
I've read that this could be caused by bad themes or plugins. So install it once again in 184.108.40.206 and setup the default/deafult theme and remove all the plugins (set to false in /etc/modules). Did the upgrade once again but sadly with the same result.
I followed the hints on this page: Fundamentals for debugging a Magento store but still no login possible and neither clues or errors.
I've a log-file during the upgrade and all seems well but 2 issues:
Checking dependencies of packages Package community/Mage_Core_Modules failed: Detected Mage_Core_Modules conflict of versions: 220.127.116.11-18.104.22.168 and 22.214.171.124-126.96.36.199 Installing package community/Mage_All_Latest 188.8.131.52 Package community/Mage_All_Latest 184.108.40.206 installed successfully Installing package community/Interface_Adminhtml_Default 220.127.116.11 Error: install: Failed to open file /home/schapenv/public_html/staging/downloader/.cache/community/Interface_Adminhtml_Default-18.104.22.168/app/design/adminhtml/default/default/template/downloadable/sales/order/invoice/create/items/renderer Installing package community/Interface_Frontend_Default 22.214.171.124
Is this a clue why I can't login?