Imported Library is not "My Library"
I imported the library from my old computer, and it now appears in Zotero as "Imported (and the date)". This is not part of "My Library" but appears beneath it. "My Library" seems to contain all the citations that were imported but does not have any of the subfolders, which are only under the "imported" library.
So effectively I seem to have two libraries. Can I delete "My Library" (and if so how) and just use the one I imported?
So effectively I seem to have two libraries. Can I delete "My Library" (and if so how) and just use the one I imported?
Your "Imported (date)" collection contains your My Library organized as it was imported. You don't really have two libraries.
At least that's how I understand it.
If that's not clear someone else should be along shortly to clarify.
So I guess my real question is, can I remove this "Imported" collection without losing the subfolders beneath it?
If you have "My Library" showing and enter a new item, it will not automatically appear in any subcollection.
You can rename the imported collection if that helps, but what I think you might want to do is drag each of your subfolders up to "My Library." (You need to do this one at at time, since you can't select all).
Once you finish dragging, your subfolders (and any other items that may not be in a subfolder) to My Library, your Imported library should be empty and all your subfolders will now be directly under My Library.
You can now delete the EMPTY (if it's not empty, drag any remaining items/folders to My Library) imported library folder.
Is that what you are aiming for?
If you are simply trying to drag items from the center pane to "My Library" you will always get the cannot copy symbol because they are ALREADY in "My Library" by definition.