Cannot back up to to current catalogue

"Available Space"

So:

1. How much hard drive space does the catalog and the preview folders, etc (not the photos) take up (uncompressed)

2. How much free space is available on the hard drive you are placing the backup in?

Note, while the finished backup will be compressed, LrC will first copy the catalog and associated folders first, then it will compress the result. So you need more space than what you see when the backup is completed.

After updating to V12.5 I can no longer backup to the current catalogue.

I am having trouble understanding the phrase "backup to the current catalogue". Normally you just make a new backup, there is no such thing as backing up to a catalog. However, when this happens and it doesn't work, how are you doing this, step-by-step? What is the indication that it doesn't work? Is there an error message? If so please provide the exact word-for-word error message.

When I go into the backup folder, all the backups are there up to the last one, but when I click on any of the folders it says 'No items match your search'.

When you try to use the backups, do you unzip them first?