If ever you're getting an error like this when importing products CSV on Magento,
Notice: unserialize(): Error at offset 925 of 1057 bytes in /var/www/magento/app/code/core/Mage/Dataflow/Model/Batch/Abstract.php on line 66
Make sure to fix special characters on the description or short_description column and other columns. For some reason, Magento does not accept those special characters like ™, ®, &, £, and a lot more.
Hope that helps...