My magento store is throwing this error:
Fatal error: Cannot instantiate interface Magento\Framework\View\Design\Theme\ResolverInterface in /Library/WebServer/Documents/magento/vendor/magento/framework/ObjectManager/Factory/Dynamic/Developer.php on line 73
I don't know why it started to appear. I made no new module installation. The store was working fine.
I've check file permissions and I see no issue there. Also delete the /var/ dir and, I think, all folders/files where created.
[EDIT] The preference is defined vendor/magento/magento2-base/app/etc/di.xml
<preference for="Magento\Framework\View\Design\Theme\ResolverInterface" type="Magento\Theme\Model\Theme\Resolver" />