WD External Drive for Backup

Yes, you could do that but then you would have no backups. That is foolish. Instead, just purchase another drive to use for this purpose. That are not all that expensive.

Is the WD drive an SSD or HD drive?

If HD is it self powered?

If you're in the market for an excellent portable SSD to carry with your laptop consider this for OWC (MacSales.com):

If budget is a concern consider this:

Not quit as elegant as the Mini but still easily transportable with a laptop.

I'd keep the WD drive with the desktop iMac and keep using it as a Time Machine drive. When It gets low on space it will delete the older backups to free up space for the new backups.

No matter what type of drive you get always erase it and reformat it before using. And don't install or use any software that may come with it.

AndySatterfield wrote:

My 2T drive is almost full of back ups after a few years. Can I erase all that and start using it for traveling, mobile data with me? Is that not a useful idea.

External drives do ware out over time. I would replace it with a new external drive for Time Machine backups. Then repurpose that one for something less stressful like weekly clone backups using CarbonCopyCloner.

I completely agreed with "Ronasara" on this issue.

Purchase another drive to this purpose!

WD is a possibility ,but try other Brands too?

Back-up is life insurance in this times!