[Helmling]

Actually, more than one.

I am at a complete loss. Somehow fiddling with DropBox's selective sync too many times in a row ended with my entire iPhoto library being deleted from all three of my Macs. Now, two of these are Macbooks with measly 128 Gb HDs. One of them was out of room, prompting me to to try to hide some folders to save space. I clicked the iPhoto Library by mistake, tried to recheck it and then it started getting sucked slowly out of all the computers.

So I go back and restore a back-up of the library and let it trickle out through DropBox. But Finder says the darn thing is 50Gb, but DropBox is only showing 37% of my 100 Gb as used and now the darn thing won't fit back on one of the MacBooks--but it's not the laptop that was running out of room!?!

I'm so f'ing confused. I don't know where my disk space went. I'm not even sure where it's going right now. The darn computer keeps giving me different reads on how big this iPhoto library is. While trying to fix this mess, I decided to upgrade to Mountain Lion...could that be the problem?

[OreoCookie]

No, I don't think your upgrade to 10.8 is the problem, at least you haven't given an indication that it is.

I think what could have happened is the following: you wanted to sync your iPhoto library across all three Macs. So you selected it to be synced via Dropbox on at least two of the three Macs. Dropbox doesn't know about iPhoto and just sees a bunch of files and folder (this is not a bug, this is how Dropbox works). As the library is big and you probably didn't wait long enough, all your three Macs were working with partially synced libraries. iPhoto is confused and does not (because it cannot) read your iPhoto library properly. It tries to update it, but eventually gives up. These changes in form of the borked library are synced back to your other Macs, destroying working copies of your iPhoto library. All the while Dropbox merrily accepts the changes and syncs borked libraries onto your other Macs. Rinse and repeat.

If that is indeed what has happened, the fault does not lie with Dropbox, but it's a classical case of user error and unintended consequences.

[Helmling]

Oh, believe me, I know the extent to which DropBox does not understand iPhoto and I don't blame them for that. But I cleared all three Macs of the iPhoto library and then dropped it into one from the backup. So all three were syncing from one copy of the library and I left them alone to do it. But the original problem wasn't that the iPhoto library got "borked." It was being deleted, thousands of files at a time.

For some reason that iPhoto library reads 24.7 Gb at the source and yet if you subtract all the other folders in my DropBox it should be over 40Gb, even though DropBox says I'm only using 36.8% of my 100 Gb. It if was only 24.7 Gb (which would fit with with the 36.8%) then it would fit just fine on my last laptop--where it did fit just fine a week ago before all this happened. Again, this is not borked. The damn thing works just fine on the two computers it's loaded onto. I've browsed through and as far as I can see, the library is complete, intact and functional.

I've looked through the iPhoto library for conflicted copies of files or "trashed" files but I don't see any, so I'm still completely perplexed.

[andi*pandi]

Brrr. sounds like a good reason not to use dropbox to sync!

[Helmling]

We've been doing it for years and before the biggest problem would be if we opened the photo library in two places at once. Sometimes the library would get out of sync that way, but it was nothing like this. I had been trying to just let photostream keep us up to date, but then it kept switching itself off and we'd have to manually drag the photos over. Maybe I should just go back to that...Isn't it supposed to be better under Mountain Lion anyway? Maybe?

Geesh. I love the features of iPhoto and I don't know of another program that could really manage this many images, but keeping them up-to-date across multiple computers is a frickin' headache. A four-day headache now...

[mduell]

Dropbox keeps the objects, so "reuploading" will be quick. The local client calculates the hash, then tell the server to expose the file with that hash to you.