How to Sync Any Mac App’s User Data with Dropbox

/ 18 March 2010

About 2 weeks ago my dad went and got a Dropbox account (I’ve had one for years), and with that had to install the Dropbox Client software onto his iMac (and MacBook Pro, but that isn’t relevant here). So, I quickly went and set up 1Password in my account on that iMac with my Dropbox account. Earlier this week a hint got posted to MacOSXHints that showed how to save an iWeb domain file to a flash drive for editing on multiple Macs. This hint was easily used with my Dropbox in place of a flash drive. But it got me thinking, why wouldn’t this same notion work to sync any application’s user data? As it turns the regular aliasing doesn’t work for root Application Support folders (the apps don’t recognize the link to valid user data in Dropbox), but using a linking method I read about in an earlier iPhone SDK release advisory I got it to work! Here is the procedure to get MyApp’s user data to be syncing with Dropbox:

  1. Move the MyApp folder in ~/Library/Application Support to somewhere in your Dropbox (for the purposes of this article that is ~/Dropbox/Synchronization/)
  2. Run this command in the Terminal: “ln -s /Users/my-short-username/Dropbox/Synchronization/MyApp /Users/my-short-username/Library/Application Support/MyApp”
  3. You should now see that the MyApp user data is back where it started but has Dropbox’s “checkmark” or “sync” icon at the bottom-left. This means that the user data is now going to be accessible to MyApp but also synced with Dropbox so MyApp on one of your other Mac’s can utilize the same user data

To set up the user data on another Mac simply do step 2 above. For most applications you will need to have the application quit for data to get synced and should not have the application running on two Macs at the same time (1Password and Growl are working exceptions). The Application Support folders that I have successfully syncing with Dropbox (but without any special setup, like 1Password) are the following:

Keep in mind that this syncing isn’t supported by any of these apps (whereas Agile Web Solutions recommends it for 1Password) so you may run into trouble or data loss. In theory any of the Application Support folders could get synced, but some don’t make sense for syncing and others just won’t work at all. So proceed with these directions at your own risk.