# Frequently Asked Questions
# Komga doesn't start, logs show error message about the database
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.