My main LR CC Classic catalog is on my iMac desktop computer. When I travel I load my photos daily on to my LR catalog on my Macbook Pro. I was urged buy LR to upgrade Lightroom CC Classic to the latest version to 7.3.1. I did so on both computers and got the message that the catalog had upgraded.
When I try to import the LR catalog on my Macbook Pro to LR CC on my iMac I get the error message "The catalog does not appear to be a valid Lightroom catalog."
I tried making a backup of the catalog on my Macbook Pro and accessing the backup. I got the same message. I tried to export the catalog to new catalog file. That also failed. I restarted LR on my iMac and Macbook Pro. Again no luck.
Any help in solving my problem is greatly appreciated.
I figured out the issue. I was accessing the Lightroom catalog on the MacBook via a Shared device over my wireless network. In this case the catalog won't open. After I copied the catalog to my iMac I could copy the items from one catalog to another.
Adobe should provide a more informative/valid error message in this situation.