# Frequently Asked Questions
# Migration from H2 to SQLite
0.48.0 is changing the internal database from H2 to SQLite. The change is done transparently.
A migration will be triggered automatically at startup:
- if the H2 database has not been migrated yet
- if the SQLite database is newly created
The regular functions of Komga will not be available during the data transfer (API, webserver, library scan…).
After a successful migration, a file with the
.imported extension will be created next to your existing H2 database (for example for the default configuration it would be
By default, the SQLite database will be located in the same location as the H2 database:
- if using the Jar:
- if using Docker:
You can customize the location of the SQLite database using the configuration
komga.database.file or environment variable
The database backup feature introduced in
0.37.0 has been removed. It might be re-added later on using a different logic.
# Komga doesn't start, logs show error message about the database
0.48.0 to avoid those issues!
If Komga does not start, and you have this kind of error messages in the logs:
org.h2.jdbc.JdbcSQLNonTransientException: General error: "java.lang.IllegalStateException: Chunk 20221 not found [1.4.200/9]" [50000-200]
It means the database is corrupt, and you need to restore from a backup.
0.37.0 Komga has automatic database backups enabled by default. You will find a
database-backup.zip file in
- Make sure Komga is stopped
- Delete the corrupt database (
database-backup.zip, it should contain a
- Restart Komga
# Media type application/x-7z-compressed is not supported
Your files are compressed using 7zip, which is not supported. Extract your archives and compress them again using the
# ChunkyTNG displays the wrong number for my books
ChunkyTNG is doing a lot of caching, you may need to remove/add your OPDS server to force ChunkyTNG to update.
# My books/series show a different name than the files/folders
Komga automatically import metadata from
EPUB files and from
cbr. The imported metadata will override the file/folder name.
# This server has already been claimed
The server cannot be claimed if a user already exists in the database. It can happen when you start Komga for the first time without the
claim profile as Komga will generate a default user.
You can solve the issue by deleting the database. By default it is located in
~ is your home directory on Unix, and your User profile on Windows.
# Tachiyomi does not show thumbnails
Make sure the URL of your Komga server starts with
https in lowercase.
# How can I disable the periodic scans?