Intact Library, metadata corrupted (half library not showing)

[puxatudo]

Hi there,

Here's MY PROBLEM:
After updating Calibre to version 6.0, for some reason, the metadata file got corrupted. Calibre then, asked me if I wanted to import the library again. I accepted.
Little did I know the metadata was corrupted.
I ended up with all my files intact but not showing in Calibre (as half of it were not listed in the "master" database file). The software probably imported a previous outdated saved file.
I ended up with half my library not showing up (around 14,000 books).
The authors' folder structure is perfect, only missing the metadata files (it also has the covers).

MY QUESTION:
Is it possible to import all the missing files in bulk? (I don't mind if I have to download their metadata from the Internet again).
I guess I can reimport all of my books and cancel the ones Calibre tells me are already in the database. But I've got around 27,000 books. I'm afraid the process can get corrupted midway.
Any advices or ideas?

Thanks in advance!

[kovidgoyal]

Create a new empty library, then right click the add books button and choose add from folders and sub folders, click yes for the all files in a folder are a single book, then choose your old calibre library folder.