Just downloaded 2.15 went to install and it appears the caches are not cleared/flushed on install? Logo and pop out menu`s missing when login to admin. I think this is the problem because I just double clicked during clearing config file on 2.14 and got the same sort of error, how do you manually flush the cache, tried just deleting the var files, no joy?
You can flush and clean cache via the CLI. Run the following in your magento root directory via the command line interface:
php bin/magento cache:flush php bin/magento cache:clean
If you still see the broken/missing content then it's worth redeploying the Magento static content. To do so, run the following in you CLI:
php bin/magento setup:static-content:deploy