Originally Posted by MartyTX
I noticed that in Find Duplicates "Cross Library Search Options" the dropdown list of libraries contains a few calibre libraries that I have deleted. I had created a few test libraries as a sandbox for learning calibre; they have been deleted using the "Remove Library" function and the folders have also been deleted.
Is there a relatively easy way to "prune deadwood" from the dropdown library list?
Go to your calibre configuration directory. Close calibre and then carefully edit the history.plist file. Inside there you will see the list of libraries from the history of usage of this combo, within the <asset> under the <key>lineedit_history_find_duplicates_plugin:libra ry_duplicate_combo</key> entry.