I found a way to deal with this issue: I noticed two things:
* it is possible, when inside the group library, to move an item from the root to a collection.
* It is possible to move an item from personal collection to group collection only if this item is not already present in the group library somewhere

So I have removed all my items on the group library, I have created manually the collections there, and then I have copied, collection by collection, the items from my collections in their corresponding collections on the group library.
And that's it.

Nevertheless two limitations still exist:
* no possibility to copy the collections from personal to group libraries and vice-versa.
* no way to move a personal item to a group collection it this item is already present in the group library

Is it worth opening a bug declaration?
Alain

I agree this is a problem. I spent considerable time setting up subcollections on My Library with the idea that, once complete, I'd move it to the Group Library for all to see and use. This didn't work. I hope this will be corrected soon.

This presents a problem for me because it is (would be) extremely useful to be able to break down my groups into a series of collections in which I can put references, including placing particular references into more than one collection when appropriate.

Well, you still can—just not directly from the personal library. At the moment you need to drag from the root of the group library instead.

Please update Zotero to enable Collection copy/move!

Please! This severely limits the utility of deferred collaboration!!!!

Golly, it's now well over a year later and this problem still exists?
I just set up a group and ran into the same problem, impossible to drag anything from my library to the group library. The documentation says this is possible, but it just is not.

Oh my goodness, I should manually create all the collections and subcollections in the group collection and then manuall drag all the items into the proper collection again??
I interpreted a collection being an item too, which, considering the amazement of the previous posters is not a common misunderstanding.
I suggest this needs fixing in such a way that you can just drag collecctions into group collections to.

http://forums.zotero.org/discussion/6982/import-a-collection-with-subcollections-into-a-group-library/#Item_21

A followup. I've been playing with this, and it seems quite difficult to use if you are expecting to add incrementally to your Dbase or you join a project that already has an established bibliography and you want to merge your own personal bibliography in.

Here's a use case:

1) You do a search of your own dbase for some topic (advanced search: "Ruthwell Cross" for example)
2) You come up with 1000 items (650 of which are already in the group bibliography).
3) You highlight everything in your search result window and try to move it.
4) (in my case), it won't do anything, so then you try smaller numbers of items till you get something that will allow you to transfer them.
5) You do so, and then you get an error that says that since some of these items were already in the group bibliography nothing has been moved.

The only way of getting around this that I can see is run the same search on the group library; write down the author-year on items that the group has on the same subject; rerun the same search on your library; manually highlight everything but the shared entries between the two; move things over and hope you haven't accidentally included a common entry and so caused the whole thing to abort.

Something you can't do is try a couple, then a couple more, and so on. Every time you do a transfer, your local library resets and you have to rerun the search.

Some solutions:
a) Flag the common items (hard given that you could be in different groups)
b) Arrange it so that a transfer flags the duplicates but completes for the rest--e.g. similar to the way sync/conflict works--rather than throw an abort error for the entire transfer if there is some duplication
c) return after an error to the last state--meaning that people could run a search and then try different combinations of entries.

I am organizing my Group Libraries and having problem moving collections and sub-collections across the Libraries. What I am doing now is to create a Collection, move all the bib entries over to the new library collection, and then delete them in the original library collection. Sometimes when I am moving entries, Zotero isn't happy and would crash.

edumf, no, you are not stupid; but Zotero is for every smart people only (joke). It looks like you can do what I am still doing right now: to move a lot of bib entries to Group libraries (I am paying so I can share with my team members the bibliographies). Anyway, this is what I do:
1. Create the collections under the Group libraries you have. I would suggest to have only one library if possible since the libraries don't talk to each other. (You can't search across libraries.)
2. Go to the Personal library and highlight the bib entries you want, and then drag and drop them into the collections you created in step 1.
3. Delete the old entries and remove the old collection after you make sure the entries are in place.

If you have a lot of entries, Zotero would crash sometimes but I don't think the entries get lost anyway.

Hope this helps.

Dear polochen, thanks for your help, but I could not export my library. One question: I need to pay to have this option? I noticed this in your comment. Dan, I have Zotero Firefox 3.0b3 and 9. Unable to drag the folders. When you talk about the bib file, I must save it and upload? Will it be a problem with any other plugin or application that I should have on my pc?
Thanks, anyway.

One question: I need to pay to have this option?

edumf: No, you don't need to pay to use group libraries.

And I guess I don't really understand what the highlighting does. . . every time I highlight an article and try to drag it into the group's library, Zotero redirects me to the listing for that article in my library!

Erin: Are you trying to drag in the online interface, or in the Zotero client? You need to do it in the latter.

yes

Just dragging the item(s) to My Library or a collection under it should work.

Sorry to be so dense but I don't see how to drag it. When I'm in the group library, "my library" is under a separate tab on the website, it's not on the same page or anything so I don't know how to drag it. Is there another way to do it? I know it's not already in my library.

Thanks.