256GB Micro SD Card now available for Dropbox

If you’ve read my previous post about¬†Using a Micro SD Card on a MacBook for Dropbox, I’ve got some pretty cool news. There is now a 256GB Micro SD card available at U3 speeds! These things aren’t cheap – this one is currently $132 as of June 2017, but I’m planning to save up for this one since this would hold everything in my Dropbox account.

If any of you readers out there is feeling generous, here is my Wish List if you want to send it to me. ūüėÄ

Here it is on Amazon




The Ideal Dropbox Setup for External Hard Drives

The problem:

  • You have a MacBook or PC with a hard drive that isn’t big enough for your entire Dropbox account.
  • You have this shiny external hard drive that could hold your entire Dropbox account¬†with space left over.

The solutions that DON’T work, or that I don’t want to use:

  • Symlinks inside your Dropbox. I’m not going to bother providing links to examples. They are everywhere. This. Doesn’t. Work.
  • Some third-party tool that assures you it will be around forever.
  • Moving your Dropbox root folder onto the external hard drive. Because if I left my laptop attached to my external hard drive all the time I wouldn’t have purchased a laptop.

The only solution that actually does work:

  1. Create a new user account on your MacBook or laptop. (you could even¬†give it a username of “Dropbox”.
  2. Setup Dropbox, signing into Dropbox with your account, but change the Dropbox root location to your external hard drive.
  3. Don’t log out. On a mac you can “switch users” so that this account on your MacBook stays logged in and keeps syncing your Dropbox. Switch back to your user account.


  • You still have Dropbox in your home folder, and you still have¬†Selective Sync. The storage on your internal drive is unchanged.
  • With your external drive mounted, you can now see all of your Dropbox.
  • I haven’t confirmed this, but I believe it uses LAN sync.
  • UPDATED on 2/13/2016: One of the commenters, Bob, pointed out in the comments below¬†that you don’t need to worry about changing file permissions on any of the files in your Dropbox folder on the external drive either. OSX¬†will treat any changes to files on an external drive as being changed by the current user. So there is no need to do any kind of massive file ownership change to what is on your external drive. Really great tip that I honestly hadn’t thought about when I started this project!

Un-mounting the external drive:

If you ever unmount your external hard drive, your Dropbox folder is unchanged. When you switch over to the other user account, Dropbox¬†throws a nice warning that simply says “Your Dropbox folder is missing.”

Dropbox doesn’t delete files from your account, and it doesn’t go about creating duplicates. It simply says “I can’t work like this” and waits until you remount the hard drive.

UPDATE Spring 2016:

I wrote this post a year ago, and during that time I found a solution that is much simpler. It may not work for everyone, but if your entire Dropbox account has less than 128GB,¬†this might just work…

I no longer attach an “external” drive, nor do I create a separate Dropbox user account. Instead I use a very¬†tiny form factor USB drive. This USB drive stores 128GB and fits so snuggly into my USB port that I leave it in all the time. It is the SanDisk Ultra Fit 128GB. I got it when it first went on sale for $29.99,¬†and in the past three months it has been holding steady at that price range.

Since my entire Dropbox account is less than 128GB, I just let it all sync to the drive and I never have to worry about it. By the time my drive is larger than 128GB, I’m hoping they’ll have a 256GB model available. ūüôā

2016-02-05 18.57.10

UPDATE: April 2016

Dropbox is working on a new prototype that might help, but it is probably a long-way from being available to most of us. The idea is that you can see the files you have on Dropbox without actually downloading them to your device. Imagine “Selective Sync” but still showing the files you chose not to download (very similar to how Dropbox works on an iPhone or an Android device).

Here is the article:



UPDATE: End of May, 2016

I have found that a USB port permanently occupied¬†has been¬†an inconvenience since there are only two USB ports on the MacBook. I’m currently experimenting with using the SD card slot instead (You can see the MacBook’s SD slot in the photo above). I never use the SD card, but I’ve had several occasions where I needed another USB port available.

A normal SD card would stick out of this port, but I have found a couple of interesting SD adapters that are designed specifically for the MacBook and, when inserted, are flush with the edge.

My first attempt didn’t work, because I glossed over the description on this adapter and didn’t realize that a “MacBook Pro 15 inch” wasn’t going to be the same size slot as is on the MacBook Pro 13 inch that I own. So pay close attention when ordering online and make sure that you are getting a Micro SD card to SD card adapter that was made for your specific MacBook.

2016-05-27 21.50.42

That one was about $8, and unfortunately, the cheapest deal I could find for my MacBook was this adapter and it cost around $25. Ultimately though, if it isn’t¬†flush with the edge of the MacBook it will get bumped and knocked out, so it has to be a perfect fit.

I’m waiting for the new adapter to arrive, but I’ve gone ahead with the Dropbox migration. I purchased this 128GB Micro SD card¬†and was using the rsync¬†command to copy files from the USB Dropbox drive to the new Micro SD Dropbox drive.

I ran into some issues¬†where rsync failed and gave some errors, and I think it may have been because the Micro SD card uses the exFAT file system as its default partition type. I started over and formatted the MicroSD card to use OSX Extended (since that is how I had formatted the USB drive) and rsync¬†has been copying without any errors so far.¬†It is still too early to say for sure if this is going to be a working long-term solution, but I’m optimistic.

I love the idea that this will sit flush in the MacBook, so I don’t have to worry about knocking it out. And I’m excited because there is already a 200GB Micro SD card¬†that has great reviews, so I have a little more room to grow if I go the Micro SD route.

UPDATE: Late May, 2016

If you plan to migrate your Dropbox from a USB drive to a Micro SD card, don’t do what I did and try to copy all of the files manually. Because when you go into Dropbox and tell it to change the location of Dropbox to the new Micro SD card, it will say “There is already a Dropbox folder there” and you’ll have to delete the folder. Dropbox insists on moving the files for you, which honestly I prefer.

Also, the right SD card adapter is worth the money. This was clearly made for my MacBook! I’m going to be keeping notes as I continue to use this device.

2016-05-28 10.09.37

One thing I’m noticing right away is the speed difference. The SD Card slot on the MacBook is much slower than the USB 3 slot. I ran a speed test for each of the two drives, the the SD card was considerably slower. I’ll consider uploading the comparison. When I saw this Micro SD card adapter, I thought this would be a cut and dry solution, but the speed is definitely a factor. At times my MacBook was crawling. Some things I’ve learned:

Make sure that you format the Micro SD card using one of Mac’s partition types. OSX Extended or OSX Extended Journaled. I was using exFAT originally and it was impossibly slow. After I switched to OSX Extended, it sped up quite a bit.

The slowness affects how fast Dropbox can actually download and sync your folder. Since the IO write times are slower, Dropbox moves slower too. For example, when I open Finder, there is a bit of a lag as folders populate.

I feel like the OS is slower overall, but I haven’t quantified this yet. When I take the card out, it seems like the OS speeds up considerably.

With the USB 3 drive, I created another folder called Applications and moved some of my larger Mac Apps over to the USB. There wasn’t any noticeable change in the performance of most apps. I haven’t attempted to do this with the SD card, because I don’t think it will be able to keep up, but I’m planning to try it. If I could move larger applications over to the SD card, that would be ideal since¬†the form factor can’t accidentally be bumped out.

Once Dropbox gets fully synced, the SD card might be a good solution for Dropbox,¬†but my gut here is that it won’t work well if you have a lot of things that write directly to Dropbox (like 1Password,¬†or using Photoshop with files in your Dropbox).

UPDATE: June 2016

I’m going to start logging all of my notes for the Micro SD card on a new post.