sync smart previews between 2 computers

[#1]

I keep all my 50k+ photos on my Windows desktop and just loaded all the smart previews [but not the photos themselves] onto my Mac laptop. [transferred via flash drive--not the cloud]. From now on, how do I find the smart preview for new photos i add to my desktop catalog and then add them to the smart previews already on my mac? [I can only use the cloud for small jobs since by broadband is lousy.]

{Moved from Lightroom Cloud to Lightroom Classic Forum by Moderator}

[#2]

I keep all my 50k+ photos on my Windows desktop and just loaded all the smart previews [but not the photos themselves] onto my Mac laptop. [transferred via flash drive--not the cloud]. From now on, how do I find the smart preview for new photos i add to my desktop catalog and then add them to the smart previews already on my mac? [I can only use the cloud for small jobs since by broadband is lousy.]

{Moved from Lightroom Cloud to Lightroom Classic Forum by Moderator}

[#3]

The basic idea and purpose of having smart previews is to be able to edit the images when the master images are not available because they are perhaps located on an external hard drive that is disconnected. In that instance the smart previews are used and the changes are saved to the catalog. When the master images are again available the adjustments will automatically apply to those master images. In your case, you don't seem to be allowing for reconnecting with the master images. At least I'm not seeing that step in your workflow. So what purpose is the smart previews filling for you?

[#4]

They may be called "Smart Previews" but really they are not 'Smart'.

Although they are smaller sized DNG files they are still "Previews" that must be connected to a Catalog.

Simply moving them to another computer/drive does not, in any way, link them back to the 'Original' image files on the Windows Desktop.

To successfully use "Smart Previews" on another computer you must "EXPORT AS A CATALOG" and include the SPs. Then you have a Catalog (with SP Previews) you can move/copy to another computer and edit the SPs, and return the edits back to the WIndows Desktop Catalog by "IMPORT FROM ANOTHER CATALOG".