How Can I Make My Second SSD a Boot Drive Without Losing Data?

If you’re looking for alternatives, starting with a USB drive for booting could work, too. Lots of options out there—you just want to ensure you have everything backed up first!

The easiest way might be to get a third SSD that’s the same size as the first one. You can use Clonezilla to clone your main drive to this third one, then resize the partitions accordingly. After that, install the third drive, and you can transfer your data from the second SSD. Just remember, since most modern laptops have NVMe slots, if your second SSD isn't NVMe, you might run into issues.

To make your second SSD a boot drive, you’ll first need to shrink the existing partition on it. You want to make enough space for the new system partition—perhaps an additional 100 to 500MB for an EFI boot partition, too. Tools like Clonezilla and GParted can help with this. Just be careful, as there's always a risk of losing data if you mess up the process, so back up everything important before you start.

Getting this to work could be a bit of a hassle. As others mentioned, you can definitely shrink the partition on your second SSD and clone over the OS from the first SSD. If it doesn’t boot properly afterward, you’ll have to dive into the recovery environment to make those cloned partitions bootable. Also, don’t forget to disable BitLocker and Secure Boot. Have you thought about using a USB to NVMe adapter to just back up your data from SSD 2?

Yes, what you’re describing is OS cloning. It's a bit finicky, in my opinion, but you could find both paid and free apps for that. I’d suggest backing up your data and maybe doing a fresh install instead, but if you prefer to clone, check out some YouTube guides. Just a heads up, though: since you only have one slot, you might need to clone to an external drive first and then migrate the OS to the second SSD after swapping them out.