Microsoft’s new Surface Book handles storage expansion quite a bit differently than all previous Surface models. This time around, we get a full-sized SD slot rather than microSD. And it comes with a major disadvantage: You can’t fully insert a card into the slot.
What this means is that an SD card—or, as likely, a microSD card in an SD adapter card—won’t fully insert into Surface Book. Instead, it hangs out off the side of the device … a lot. Like half an inch. And because there’s no mechanism to hold the card in place, it’s easy to dislodge by mistake.
Long story short, you can’t rely on this slot to expand the storage of Surface Book permanently. Instead, the slot is relegated to temporary file copies, perhaps from a digital camera or other device.
And that’s too bad. With all previous Surface devices, Microsoft provided a tucked-away microSD card slot, under the kickstand, which let one permanently expand the device’s storage. Then, you could use Windows to default to that storage for documents, music, videos, and photos, and, with Windows 10, apps as well.
Because you can’t do this with Surface Book, you will need to plan ahead. One option is to purchase a Surface Book model that provides enough internal storage for now and the future. And this means you may be spending more up front to purchase a higher-end model than you might otherwise.
Alternatively, you could consider a low-profile SD card, which is designed to overcome this issue, which isn’t unique to Surface Book. Such cards exist, as do low-profile microSD adapters (here’s an inexpensive example), and they protrude less but can of course still be dislodged by mistake.
As with any other Windows device, you can also also use USB-based external storage, and can take advantage of OneDrive or other cloud services for additional storage, assuming you have connectivity.