The issue is this: when backing up (cloning) many small files, the progress is not helpful in terms of gigabytes copied, so it is not apparent how far along things are which means it becomes inscrutable as to how long it will take (the progress indicator is not accurate in such cases).
1. Quit Carbon Copy Cloner and paste the following into a Terminal window (press the return key when done).
defaults write com.bombich.ccc showDetailedTransferStats -bool YES
2. If done correctly, the value should read as "1" with this command:
defaults read com.bombich.ccc showDetailedTransferStats
As shown, entering those commands looks like this (stuff in blue is what was entered).
diglloyd-iMac:MPG lloyd$ defaults write com.bombich.ccc showDetailedTransferStats -bool YES diglloyd-iMac:MPG lloyd$ defaults read com.bombich.ccc showDetailedTransferStats 1
With this setting, the progress shows files compared, files copied, and gigabytes copied. This is much more useful when getting a sense of how far along it is. I’m not sure why this is not the default, or why the option is not in the Preferences dialog.