You won't be able to sync Zotero databases with Groove, since the records are stored in a database file which Groove has no way of combining. If Groove has the ability to sync files, you might be able to get it to regularly replace one zotero directory with another, but you have to have a way to always know what you are doing, since you can clobber the wrong directory if you're not careful.

And you shouldn't have to use portable firefox in particular. You only need that if you don't want to mess with trying to sync them, and you want to keep a single database.

You can sync your zotero data directory, but at the moment, only if 'sync' means clobbering one data directory by another. I sync my zotero databases between a few computers and a portable firefox directory on a USB, but that never means I can merge two databases with different items, it always means getting all the new files from one place and adding them to another place. This will include the all-important database file itself (*.sqlite). The process of replacing that database file will make any new items in your destination directory inaccessible.

If you have different items in two Zotero directories, (you added some on your desktop and then some on your USB drive) the only way to merge them is to export from one (to Zotero RDF, including files if you like) and import them into the other. It will not be this way forever, but it is now.

The implication of this is that at present you have to have some way of keeping track of the state of your various Zotero databases compared to each other. If you have a way of always keeping a certain one as the 'most recent,' and remembering when you have new additions to two databases simultaneously, which one is most recent, you're fine (so long as you keep the Zotero versions the same). If you can't manage to do that, it'll escape you.

Hope this helps

I do not see how synchronize programs/web spots can ever work since there is a database to be updated, not written over. It must be through Zotero and some probably reasonable sql.

OK, here's my "solution," which is just what scot says with my twist. On my primary computer, I'm keeping my primary zotero database in a separate location, in a folder under my docs, not that it matters where, but I can hunt it down in a hurry if need be. (Preferences, Advanced, Storage Location, Custom). On a USB stick I have Firefoxportable and I copied my primary computer's firefox config onto there. On the portable Zotero, erase all collections, everything. MAKE SURE THE STORAGE LOCATION FOR DATA ON PORTABLE IS SET TO DEFAULT. On primary computer, export RDF, I'm not doing files due to size, and I don't need them for what I'm doing with the portable, i.e., going to the library so the darn proxy thing doesn't gripe me. Start portable firefox/zotero, import RDF. A beautiful feature is that the database is imported into an automatically time-stamped collection. Thank you whoever did that one. Now, I can go do my thing, and just save my work in a different collection(s). Once back at the crib, I delete everything in the time-stamped collection, and then I export the RDF, with files, and import it into my primary. Again, since the import is time-stamped, you should know what's up. Use collections wisely, and life is easier.

A horribly convoluted way, I know, but it works, I don't get tons of duplicates (please fix, I'm using end note to get rid of them, ugh), and I know what data is new, and what's not.

Doubt this helps