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Beewee - how big is
part-0001.calibre-data? It should be a bit bigger than the sum of all the libraries you exported - i.e. about 3GB. When you did the export did you select one or more libraries (ctrl/a to select all) - viz
From what you're describing it appears that it may have only imported your configuration data. Is there an
%appdata%\calibre folder, that contains something like this?
dictionaries
fonts
metadata_sources
plugins
resources
shortcuts
store
catalog_presets.json
cover_generation.json
customize.py
...
...
viewer_dictionaries.json
viewer_themes.json
windows_open_with.json
BR