Some books disappeared

[waldektroc]

Some books from my library disappeared.
Books' files are gone. Folders are in place. Metadata is unchanged (although .opf files are missing too).

I did not perform any file operations besides of Calibre interface. I do not see any rule on which ones are deleted. I have noticed only that if a book is deleted then whole folder contents has gone, not just one file (one book format).

Files are not present in the Trash folder.

Library is stored on Qnap NAS. I know (now) it is not recommended but I have it accessed from one PC only, one Calibre (portable) installation. My laptop's SSD is too small to keep everything locally.

I do not exactly know when the files disappeared but it was during last few days. I have updated Qnap firmaware a few days ago as well (not sure if it is related to the issue).

Is there any chance to recover missing files?

How to prevent such incidents in the future (maybe next fakies are being deleted even right now)?

[chaley]

Originally Posted by waldektroc

Is there any chance to recover missing files?

Run Check Library (Library button / Library Maintenance / Check library.) The books may be left behind, marked as not in calibre's database. If they are not then they are gone.

How to prevent such incidents in the future (maybe next fakies are being deleted even right now)?

I know you don't want to hear this but...

Stop using the NAS. If you don't then you will lose books again.

[waldektroc]

Originally Posted by chaley

Stop using the NAS.

Is an external USB drive OK instead?

Originally Posted by chaley

Run Check Library (Library button / Library Maintenance / Check library.)

I expect this function to be useful in opposite case, i.e. files are present but DB is corrupted?

[chaley]

Originally Posted by waldektroc

Is an external USB drive OK instead?

Yes, assuming it is reliable.

I expect this function to be useful in opposite case, i.e. files are present but DB is corrupted?

Yes, it is useful in that case too. The tool finds book formats not in the database or book formats the database says should be in the filesystem but aren't.

Often the NAS problem manifests as a failure to move books when the author or title of the book changes. The new folder is created but the books are left behind in the 'old' folder. The 'old' books are flagged as extra. The formats not in the new folder are flagged as missing.