Did you find the problem/solution? I am having the same issue with a client. I'm on a pc and my client is on a mac, but I have edited catalogs from other mac users without a problem, but I keep having this issue with the same client.
The answer- you do not import the Smart Previews. You cannot! (Only original image files can be 'imported')
Melanie, You, as the 'Editor', should only OPEN the Catalog that is sent from the Client.
An "Import from another catalog" is not necessary.
You work with the Catalog (and Smart Previews) that the Client sends you.
I am reasonably sure that if you do this, the Client Catalog will open with all your presets available to do the editing. (Lightroom will use your global preferences)
Then you will only need to return the 'Editing' Catalog back to the Client (Smart Previews not needed. Even send the Catalog as a small ZIP file)
The Client needs to send you the 'Editing' Catalog by-
1. Selecting the FOLDER of images for you to edit.
2. Right-click to [Export this Folder as a Catalog]
3. Save the exported catalog folder with a suitable name (eg. "Editing" )
4. Options- NO "Export Negative Files", YES "Build/Include Smart Previews"
5. Send this folder to you (the Editor)
Upon you returning their Catalog, the Client does an "Import from another Catalog" bringing your edits back into their Master Catalog.
Some of these steps may need more explanation if I have not made it clear enough.
Thanks for the input wobertc, I am just trying to open the catalog file (not importing). I think there is an issue with the way our clients are exporting the smart previews catalog in their Macs. I also am on a Windows PC receiving a smart previews catalog from a client who is using a Mac. The odd thing is that it works just fine on any Mac, but it will have erros on any PC.
I don't see how this can be a PC vs Mac issue, because the majority of my other clients are sending me smart previews catalogs from Macs and I never have this issue. I have had this issue every time with the same client. I have shared with her the steps you provided for exporting. But isn't it odd that the current smart previews catalog in question works fine on a Mac and not on a PC?
Andy, (Melanie may no longer be following)
No answer- sorry.
Can only suggest you work closely with the client to determine exactly how they are exporting their catalog with smart previews.
Ask them to list their exact procedure, step by step, with options.
You should be receiving a folder with something like the screen-clip below, the file dates all the same?-
Just a thought- Maybe they are creating the catalog (without including the Smart Previews option) and then copying the smart previews folder from their master catalog. The exported catalog and SmPreviews would not then match.