If you cannot move or copy large-size folders from one external HHD to another external HDD, then this post will help resolve the problem. Moving a large size file or a huge folder is not uncommon.

OWC’s just-released Copy That application frees up space on iPhone or iPad by transferring images or videos to external drives. Alternatively, it can easily back up an collection of these files. And ...

Using an external hard drive: You can transfer photos and videos from an external hard drive to an iPhone, iPad or iCloud by using a camera adapter. Using Airdrop: If you want to transfer files ...