Collections syncing is one of the planned features for Zotero which is not currently implemented. This is functionality which we look forward to eagerly, but (according to what I gather from the forums and Zotero site) can't be expected before summer 2007. They are still working up to a non-beta 1.0 release, though many of us have found
Zotero very useful in the meantime.

It is possible to sync your Zotero data directory to USB (or a network folder or web filestore) and then re-sync it with another computer. You do need to be a little careful when doing this: make sure both Zotero installations are the same version (Zotero is being updated fairly rapidly), backup your data before overwriting it, etc. It's not ideal, since you need to manually take care to sync (I use Allway Sync to USB), but it has worked for me for a few weeks now.

It is also possible ( but unsupported, I gather) to store your Zotero data directory on a network filesystem and use it from there. This eliminates the step of syncing, but might require more caution to make sure your data doesn't get corrupted.

The other option which I haven't tried is to keep a Zotero database on both computers, sync the data every once in a while (as needed) and when you add a few new things to the database of the computer you are on, export them to a file and re-import them.

The final option for using on different computers is using Zotero with Portable Firefox on a USB stick, and keeping a single database there.

The synchronization stuff is still coming soon. There are many threads in the forums on handling multiple machines right now; possibilities include import/export in RDF, installing portable Firefox and Zotero on a USB drive, and using the preference setting for the location of the Firefox profile.

Putting zotero on a portable drive doesn't solve the question of synching and (most importantly) backing up.

Diligent users of external drives will backup the whole external drive! It doesn't solve all syncing issues, but it GREATLY lessens them for the single user (as one person could practically run a single copy of Zotero at anyone time, despite the fact that they might run the single copy of the database on multiple PCs)

I'm not even sure where the zotero stuff lives on my computer,

As Dan hinted, it is stored with your Firefox profile by default. This is directly answered in the FAQ. Note that you can also change the location of the storage directory from the default.

Maybe there's a reason why this isn't mentioned as an option in the FAQ?

As above, it is in the FAQ!

References to "import/export in RDF" and "using the preference setting for the location of the Firefox profile" don't mean anything to me.

Open zotero & click the gear icon. You'll see options to import and export. One format you can import/export is RDF. This preserves much (not yet all) of the info in your Zotero database. Under the gear icon is also the zotero preferences. One preference is to change the location of the Zotero data directory from your firefox profile directory to someplace else.

yes, eng, you've got it right, with the following important caveat: Since Zotero stores its data (as opposed to the attachment files) all in a single database file, you can't actually *merge* the contents of two Zotero sessions on two different computers. You can only replace one with the other.

I sync regularly between my laptop and work pc using a usb stick as an intermediary and have had no problems with this method, but I do have to mentally keep track of where the newest version of the Zotero database is. If the computer I'm working on doesn't have it, then I need to sync before I start work (and it's important that firefox not be running for this). Because of this I don't include the Zotero directory in my regular sync, just to force myself to be deliberate about which way I'm syncing it.

If I do some Zotero work and forget to sync, and want to do some more work on another computer, then I have to export the new stuff and then import it back in (after the sync, or import it back into the up-to-date database). This is the workaround for the times when you do need to merge. If you are able to always sync after a Zotero session and before your next one, you won't ever have to do this.

And one more caveat: you'll want to be aware of when a new version of Zotero itself comes out as well, since (till now anyway), new versions of Zotero have updated the database structure. You need to make sure that you don't try using the same Zotero directory with different versions of Zotero. This would normally not be a problem if each of your 3 computers have an internet connection, and you have firefox set to update Zotero versions as soon as they come out.

I've read this thread but I'm an idiot when it comes to this tech stuff.
Let me just see if i understand. I've got a USB memory stick. I plug that in, I install Portable Firefox on that USB stick... I load up Portable Firefox straight from the USB and install Zotero. And then from now on, whenever I want to use Zotero on any computer, I plug in the stick and run it from there and nothing will be stored on the main drive of whatever computer I happen to be using at that time -- only on the stick, right?
And if I want to backup that database, I can just copy the whole firefox directory from the stick directory to somewhere?
Now, when Zotero implements some sort of feature that makes this obsolete, will it be an easy matter to get this data off the stick and into some central location?
thanks.. this software is amazing and I want to set it up right first.

Hey there, it's been a while. I'm now comfortable with using portable firefox (on a portable firewire drive) but I don't see a "zotero data directory" anywhere on the drive. The drive contains the application, period. Well, it also contains copies of my "documents" and "pictures" folders (where I keep most of my user-generated files). But no zotero data directory. Which means I still don't know how to backup zotero. I had no problem importing the firefox profile from my computer to my portable. But I don't see how to go in reverse.

I'm using portable firefox version 4.0 for Mac OSX. The link you posted sends me to a "404 Not Found."

Listen, as a historian I'm considered pretty tech savvy by all of my colleagues. I was a relatively early adopter of Endnote back in 2000, although I'm more than happy now that the dissertation is complete to move on to something else (and to recommend it to students and colleagues), as long as I can use it in more than one place, and as long as I have a way of backing it up. But I have no idea what "do a recursive grep for files you expect in the profile" means. I think the FAQ section using portable firefox/backing up needs to be fleshed out more, particularly now that zotero is being bundled with the campus edition of firefox. I do not want students to come crying to me come deadlines that their jump drive ate their homework.

Would simply dragging portable firefox to the hard drive of my various "local" machines (the machine at home and in my office) accomplish the goal of creating a backup? I've stopped using regular firefox entirely anyway.

noksagt: by the reference to the campus edition she simply means that thousands of students are likely to start using Zotero now, and she thinks the backup advice in the FAQ not sufficiently easy to understand for the new masses. It has no specific relation to the portable edition.

Looking over the FAQ documentation, I agree with her that it could be improved at a few points.

(1) Since following the FAQ's advice and using Portable Firefox does expose your data to the additional risk of loss, we could usefully include a section on "How to back up your database" (including where to find your profile on any common portable versions, and on Linux). I realize portable versions are a bit of moving target, but perhaps not so much so that it's not worth keeping helping people find their profiles. And people using Z extensively will want to backup their profile every day. Backing up the whole flash drive, or even the whole Portable Firefox installation is a little over the top, particularly if you're stuck with USB 1. Every Zotero user needs to know where her profile is (don't you agree?)

(2) Friendly encouragement to backup your profile should be given in any case. I can't find any in the documentation.

(3) The useful discussion from the forums (this thread even) on syncing your data, could usefully be given a place in the FAQ. I know (or I think I know) that this method remains unsupported, and should therefore carry the customary cautionary warnings, but (a) heaps of use profile syncing regularly without issue and (b) it is very useful for those who change machines, and therefore not surprising that it keeps coming up on these forums. It might simplify things to have a good guide written, perhaps even on a page of its own in the docs. It will still be a while yet before we get the Promised Land of sharing and syncing, and even when we do, I bet that syncing the /zotero directory will still have its uses.

Right now the link in the FAQ called "use a USB drive to synch your data between computers" only links to this, a paragraph about using Portable Firefox, which isn't really a method to 'sync' information, but to move it. That could be redone.

Thanks, Scot, that is indeed what I meant. Thanks also noksagt for such quick replies. I believe I am using the same version of portable firefox, and I tried your test of dragging it and reopening and it worked. So it's all good. But I urge you to redo the documentation. Also, I read elsewhere in these boards that zotero gets very slow when you exceed a certain number of entries--my Endnote library has 4000--is that still true? This has all been prefatory to *considering* switching.

I've added a "Show Data Directory" button to the Storage Location section in the Advanced pane of the prefs. It'll be in the next release.

I have added How do I back up my Zotero library? to our most frequently asked questions page section of the faq.

Scot wrote that "It is also possible ( but unsupported, I gather) to store your Zotero data directory on a network filesystem and use it from there."
It's what I'm trying to do, but fail...
Can someone explain how to do that ?
(I try with NetDrive, but it's impossible to choose the FTP-located emulated hard drive in Zotero preferences...)

I've developed a very simple approach to: a) keep different databases by topic and b) synchronizing across multiple computers (mac, win and linux). The approach is detailed in http://forums.zotero.org/discussion/1825/importing-exporting-my-library/ the key is to COPY the Zotero directory and NEVER import/export. Copying preserves the reference IDs used in linking with Word/OpenOffice/etc.
Syncing between folders is an easy problem solved with ChronoSync, SyncToy, SyncBack, Rsync, .Mac, etc. (pick your favorite tool).

Although Zotero is a wonderful application I'm finding it very hard to sync collections.

server-based sinking is being beta tested, so is on the way.

I use SyncToy, but for some reason, although it appears to sync the sqlite files where the Zotero data is stored - the "date modified" of the sqlite file is updated every time I do a sync - the actual references themselves do not appear to be transferred across

I suspect that the problem is that you aren't sinking to and/or from the correct location. You should verify that your zotero storage directory is the same as what you're actually syncing. Also look at filesizes and/or checksums to see if files change. Finally, note that this should all be done when firefox is closed & the database is not in use.

I've tried keeping the data in Portable Firefox, but the same thing happens.

I don't think you're doing this correctly either--portable firefox should use the same profile everywhere (it resides on your USB stick). Again, close any local copy of firefox & then launch portable firefox. You can create some unique data in firefox portable (homepage and/or bookmarks are easy to change) & use the presence or absence of these to check whether you are running the portable version or not.

It therefore appears that SyncToy (which I think is the most widely used syncing application) for some reason cannot handle the sqlite files. Is this due to the funny extension, which certainly doesn't look like a Windows extension?

SyncToy doesn't require the old DOS-style '8.3 filenames,' so I doubt this is the reason & other people reported success with SyncToy.

Thanks for that. I think my basic error is forgetting to close down Firefox while doing the sync. Now that I'm careful to do so, things appear to be syncing well.

Best wishes

Nick