CantOpenError: unable to open database file

[PaceyIV]

I've followed the tutorial https://www.mobileread.com/forums/sh...d.php?t=251201 to setup a Windows Visual Studio Environment to check what is wrong.
I've created a new network drive and I do some tests.

Calibre works on my network drive if I mount it on a root share folder (es. net use X: \\ip-address\folder). If I use Calibre inside a subfolders and I mount it as a network drive it fails (es. net use X: \\ip-address\root-folder\sub-dir).
I don't understand why.

[kovidgoyal]

Do not use network drives for your calibre library https://manual.calibre-ebook.com/faq...rked-drive-nas

[PaceyIV]

Ok, you warned me, but I will continue to use Calibre on my network disk.
I use the windows portable version only from my Windows desktop to add books. From my network and outside I use cobs https://github.com/seblucas/cops to access my libraries.

The problem I've found is only a network map problem.
SQLite can works on network share.

"If you have many client programs accessing a common database over a network, you should consider using a client/server database engine instead of SQLite. SQLite will work over a network filesystem, but because of the latency associated with most network filesystems, performance will not be great. Also, the file locking logic of many network filesystems implementation contains bugs (on both Unix and Windows). If file locking does not work like it should, it might be possible for two or more client programs to modify the same part of the same database at the same time, resulting in database corruption. Because this problem results from bugs in the underlying filesystem implementation, there is nothing SQLite can do to prevent it."

https://www.sqlite.org/whentouse.html
Samba should also provide all the same locking semantics that Windows clients expect. Can follow symbol links.

I'm not using it in a concurrency way. I don't wont to waste my local drive with this libraries. I use a portable version from a network drive instead of a USB storage.

[greeman]

Originally Posted by Zepa77

Hi,

I've downloaded Kindle 1.17.44170, then downloaded my books, But when i drag them over to Calibre, I get the following error message. I am singularly nontechnical, so have no idea what to do about it. I assume I've done something wrong in the download, but can't figure out what.

calibre, version 3.19.0
ERROR: Errors while adding: Failed to add any books, click "Show details" for more information


----------------------------------------------------------------------
Failed to add the book: Devil Water
C:\Users\zepa7\AppData\Local\Temp\calibre_vkfgjj\p rehzx_add_books\0\B00IRIFYF8_EBOK.azw3
With error:
Traceback (most recent call last):
File "site-packages\calibre\gui2\add.py", line 399, in add_book
File "site-packages\calibre\db\legacy.py", line 224, in create_book_entry
File "site-packages\calibre\db\cache.py", line 63, in call_func_with_lock
File "site-packages\calibre\db\cache.py", line 1566, in create_book_entry
File "site-packages\calibre\db\cache.py", line 1287, in set_metadata
File "site-packages\calibre\db\cache.py", line 1113, in update_path
File "site-packages\calibre\db\backend.py", line 1574, in update_path
File "site-packages\calibre\db\tables.py", line 135, in set_path
File "site-packages\calibre\db\backend.py", line 845, in execute
File "c:\t\t\apsw-j6gj96\apsw-3.13.0-r1\src\cursor.c", line 236, in resetcursor
CantOpenError: CantOpenError: unable to open database file

FYI. I had the same problem and fixed it by turning off "Ransomware Protection" in Windows defender.

[allenrichon]

Originally Posted by kovidgoyal

That error is typically caused by an antivirus program blocking calibre from accessing its database. Either disable it or exclude the calibre library folder from its scans.

Hi Kovid,

I have been using Calibre for many years and have really enjoyed the ease of use. Unfortunately it no longer works as described by the posts here. I have disabled all firewalls and virus protection. I have made sure to install the software on the parent C drive. I have even tried running the program in safe mode on my windows 10 HP Pavilion. All with no luck. I really hate not being able to add to my library and manage all of my books. Hope you will be able to track this down for us!

Best regards,
Allen

[allenrichon]

Originally Posted by greeman

FYI. I had the same problem and fixed it by turning off "Ransomware Protection" in Windows defender.

Really appreciate your comment! Unset this and Calibre is now working as it should. Thank you, thank you!!!!

Best regards,
Allen

[emckechnie]

Thank you so much for the solution! Calibre stopped accessing any files and I couldn't load any books. After reloading Calibre and unloading multiple times I found this list and I went into Windows Defender, disabled the Ransomware Protection and voila! It works again!! Mind you, I had to google for instructions on how to do it but it works!

[Jyrki]

Originally Posted by theducks

NAS and other networked drives are not supported (and iffy, if you ever got them to work).
Adding books in calibre is very complex (file system wise). You create folders, add 2 or 3 files (single book format), update the DB.

All this has to happen in order and quickly.

In your case, something is blocking or slowing down one of thos steps, so another fails.

This is everything but wise.

Yep, I have the same problem. (And I really want to keep my DB on NAS.)

[theducks]

Originally Posted by Jyrki

This is everything but wise.

Yep, I have the same problem. (And I really want to keep my DB on NAS.)

Mirror (one way) it to the NAS. Free file sync can do that and it is pretty fast.

[DoctorOhh]

Originally Posted by Jyrki

Yep, I have the same problem. (And I really want to keep my DB on NAS.)

Do you want the database on the NAS or just the library? You can set a DB environment variable and have the DB on the local drive and still have the library elsewhere.