[davidfor]

Originally Posted by compurandom

Would it be possible to tell calibre to delete the collection on the device but NOT propagate that deletion to the kobo servers?

There is no way to put a collection on a device so that it doesn't sync.

Or, maybe, have a list of collections that it doesn't ever delete even if empty (similar to the existing list of ones it ignores on the device), or maybe not delete them if there are books in the calibre library (but not on device) in the collection?

That's complicating things way to much. It would need extra options to say which collections to treat in these ways and which not to. I'm not interested in going that way.

I don't want to turn off the option in case I rearrange my collections, but at the same time, I don't want collections on my other device deleted if there are still books in it... :-/

I suppose I could turn off the option and turn it back on if I notice piles of empty collections.

That is the simplest thing to do. Do you really change the collections that much that you would see this happening frequently?

But it wouldn't be too hard for me to do a couple of searches and generate a list of collections to leave alone that aren't shared between devices.

I wonder if churn of collections not mutually shared is causing my long sync times.

The more changes made, the more things to sync, the longer it takes. But, I doubt if this is where the time is. If you watch the sync, it shows the stages and you can see which is taking the time.