Is there hard drive initialization software that spares bad blocks?
If you do the Write All Zeroes option in Disk Utility (on a Mac), this is supposed to set aside all the bad blocks (be forewarned, it can take a loooong time–we’re talking many hours here for a large drive.) That said, if a drive has confirmed bad blocks, I personally don’t consider it worth the risk; in most cases, blocks going bad is a condition that continues to worsen. I’ve had one drive that behaved for a long time after a Write All Zeroes format; and multiple drives that just kept failing. So I don’t bother any more. Drives are inexpensive enough, usually, that’s it’s wiser to replace them. Unfortunately your drive is external, so SMART Utility won’t be able to access its self-monitoring attributes. Programs like TechTool Pro (Mac) can do a surface scan and alert you of bad blocks; this takes a long time and can further degrade a failing drive, so back up your data first. Disk Warrior (Mac) can also put up messages while it runs, like “Speed inhibited due to drive malfunction”,
