- Find targeted fixes for common calibre problems.
- Browse guides grouped by feature and issue type.
- Troubleshoot devices, libraries, conversions, servers, and plugins.
- Installation, Startup, and General Operation
- Library Storage, Backups, and Recovery
- Search, Filters, Duplicates, and Library Views
- Metadata, Covers, and Book Organization
- Device Detection and Connections
- Sending Books to Devices and Kindle
- Email Delivery Problems
- Conversion Failures and Format-Specific Problems
- Conversion Layout, Text, Images, and Navigation
- E-book Viewer Problems
- Edit Book Problems
- Content Server Access and Networking
- Content Server Features and Accounts
- Plugins and Network-Dependent Features
- News Downloads and Recipes
- Command-Line Tools
Use this troubleshooting hub to find focused help for calibre installation, libraries, devices, conversions, metadata, the E-book Viewer, Content Server, plugins, command-line tools, and other common problems.
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1. Installation, Startup, and General Operation
Start here when calibre will not install, launch, update, or operate reliably on your computer.
- calibre Installer Not Working
- calibre Not Starting on Windows
- calibre Not Starting on macOS
- calibre Freezes or Crashes
- calibre Automatic Update Missing
- Antivirus Blocking calibre
- calibre Permission Denied Error
- calibre Jobs Stuck or Never Finishing
- calibre Preferences Not Saving
- calibre Run From USB Stick Not Working
- calibre Window Opens Off Screen
- calibre Toolbar Button Missing
2. Library Storage, Backups, and Recovery
These guides cover damaged or missing library data, storage locations, backups, transfers, and calibre's managed folder structure.
- calibre Backup Library Not Working
- calibre Restore Library From Backup Failed
- calibre metadata.db Missing
- calibre Library Seems Corrupted
- calibre Library Location Path Problems
- calibre Library on Network Drive Errors
- calibre Library Slow With a Large Collection
- Move a calibre Library to a New Computer
- Understanding calibre's Folder Structure
- calibre Save to Disk Folder Structure Wrong
- calibre Book List Blank
3. Search, Filters, Duplicates, and Library Views
Use this section for problems finding, filtering, displaying, or consolidating books and records.
- calibre Search Not Finding Books
- calibre Full Text Search Not Working
- calibre Saved Search Not Working
- calibre Virtual Library Not Working
- calibre Tag Browser Not Updating
- calibre Custom Column Not Showing
- calibre Formats Column Not Showing
- calibre Duplicate Books Not Detected When Adding
- Merge Duplicate Books in calibre
- Remove Duplicate Books in calibre
4. Metadata, Covers, and Book Organization
Find help correcting downloaded metadata, covers, names, series, tags, and other catalog information.
- calibre Metadata Download Not Working
- calibre Metadata Download Picked the Wrong Book
- calibre Metadata Download Wrong Language
- calibre ISBN Metadata Not Found
- calibre Covers Not Downloading
- calibre Cover Image Wrong After Metadata Download
- calibre Author Sort Wrong
- calibre Series Order Wrong
- calibre Tags Not Updating
- calibre Comments Metadata Not Showing on Reader
- calibre Bulk Metadata Edit Not Applying
- calibre Bulk Metadata Search and Replace Went Wrong
5. Device Detection and Connections
These articles address USB, wireless, folder, mobile-device, and reader detection problems.
- calibre Kindle Not Detected
- calibre Kobo Not Detected
- calibre Android Device Not Detected
- calibre iPad or iPhone Not Detected
- Reset calibre's Ignored Device Setting
- calibre Device Mounted Read-Only on Linux
- calibre Connect to Folder Not Working
- calibre Wireless Device Connection Not Working
- calibre User Defined Device Plugin Not Working
6. Sending Books to Devices and Kindle
Use these guides when transfers fail, the wrong format is sent, or books and covers do not appear correctly.
- calibre Send to Device Not Working
- calibre Sends the Wrong Format to a Device
- calibre Books Not Showing on Kindle
- calibre Books Not Showing on Kobo
- calibre Cover Not Updating on Device
- calibre Kindle Cover Replaced by a Generic Cover
- calibre Kindle ColorSoft Covers Not Showing
- calibre Kindle Collections Not Syncing
- calibre Kobo Database Error
7. Email Delivery Problems
This section covers Send to Kindle, SMTP authentication, queued email jobs, and unsupported delivery formats.
- calibre Send to Kindle Email Failed
- calibre SMTP Authentication Failed
- calibre Email Jobs Stuck in Queue
- calibre AZW3 Not Emailing to Kindle
- calibre MOBI Email Delivery Stopped
8. Conversion Failures and Format-Specific Problems
Find solutions for conversions that fail, produce oversized files, or mishandle particular source and output formats.
- calibre Conversion Stuck or Failed
- calibre Conversion Settings Not Saving
- calibre Conversion Output Too Large
- calibre AZW3 Conversion Not Working
- calibre KEPUB Conversion Not Working
- calibre EPUB Conversion Formatting Broken
- calibre DOCX Conversion Formatting Broken
- calibre PDF Conversion Problems
- calibre PDF to EPUB Line Breaks Wrong
- calibre DjVu Conversion Text Missing
- calibre Comic Conversion Pages Out of Order
- calibre ACSM File Not Opening
9. Conversion Layout, Text, Images, and Navigation
Use these guides when a completed conversion has incorrect typography, ordering, images, page structure, encoding, or navigation.
- calibre Font Size Wrong After Conversion
- calibre Line Spacing Wrong After Conversion
- calibre Page Breaks Wrong After Conversion
- calibre Images Missing After Conversion
- calibre HTML Files in Wrong Order After Conversion
- calibre Non-English Characters Broken After Conversion
- calibre Smart Quotes Garbled After Conversion
- calibre Table of Contents Missing After Conversion
- calibre MOBI Table of Contents Wrong
- calibre EPUB Validation Failed
10. E-book Viewer Problems
These articles address opening, displaying, navigating, annotating, and looking up information in the calibre E-book Viewer.
- calibre E-book Viewer Not Opening Books
- calibre E-book Viewer Black or White Screen
- calibre E-book Viewer Fonts Missing on macOS
- calibre E-book Viewer Highlights Not Saving
- calibre E-book Viewer Dictionary Lookup Not Working
- calibre E-book Viewer Page Turning Slow
- calibre E-book Viewer Scrolling Mode Not Working
11. Edit Book Problems
Find help opening, checking, previewing, styling, navigating, and saving books with calibre's editing tools.
- calibre Edit Book Not Opening
- calibre Edit Book Check Book Errors
- calibre Edit Book Live Preview Not Updating
- calibre Edit Book CSS Not Applying
- calibre Edit Book TOC Editor Not Saving
- calibre Edit Book Save Failed
12. Content Server Access and Networking
Use this section when the Content Server cannot be reached or has address, port, browser, internet, proxy, or HTTPS problems.
- calibre Content Server Not Reachable
- calibre Content Server Works Locally but Not on a Phone
- calibre Content Server Internet Access Not Working
- calibre Content Server Shows the Wrong IP Address
- calibre Content Server Port 8080 Blocked
- calibre Server Port in Use
- calibre Content Server HTTPS Not Working
- calibre Server Reverse Proxy Not Working
- calibre-server Linux Service Not Starting
- calibre Kindle Browser Content Server Not Opening
- calibre OPDS Catalog Not Loading
13. Content Server Features and Accounts
These guides focus on Content Server downloads, authentication, library switching, offline use, and reading progress.
- calibre Content Server Download Button Not Working
- calibre Content Server Password Not Working
- calibre Content Server User Accounts Not Working
- calibre Content Server Multiple Libraries Not Switching
- calibre Content Server Offline Cache Not Working
- calibre Content Server Reader Position Not Saving
14. Plugins and Network-Dependent Features
Find help installing, updating, configuring, or diagnosing plugins and outbound network access.
- calibre Plugin Install Failed
- calibre Plugin Update Failed
- calibre Plugin Customization Not Saving
- calibre Plugin Causing a Startup Crash
- Outbound Proxy Issues in calibre
15. News Downloads and Recipes
Use these guides for failed news downloads, recipe authentication problems, and schedules that do not run.
- calibre News Download Failed
- calibre News Recipe Login Failed
- calibre News Download Schedule Not Running
16. Command-Line Tools
These troubleshooting articles cover calibre commands for conversion, metadata management, database access, and metadata retrieval.
