You can replace vendor directory with the new one.

By the way Its Factory method error , you can resolved this by following below steps.

1. Remove var/generation , var/cache , var/page_cache directory
2. run php bin/magento setup:upgrade command
3. run php bin/magento setup:di:compile command
4. run php bin/magento setup:static-content:deploy command
5. run php bin/magento cache:clean and php bin/magento cache:flush command

You can replace vendor directory with the new one.

By the way Its Factory method error , you can resolved this by following below steps.

1. Remove var/generation , var/cache , var/page_cache directory
2. run php bin/magento setup:upgrade command
3. run php bin/magento setup:di:compile command
4. run php bin/magento setup:static-content:deploy command
5. run php bin/magento cache:clean and php bin/magento cache:flush command