FATAL ERROR: Cannot read properties of undefined (reading 'key')

Operating system

Linux

Joplin version

3.5.12

Desktop version info

Can't retrieve

Sync target

Joplin Cloud

Editor

Markdown Editor

What issue do you have?

Not sure what I was doing at the time, but CRASH. Tried opening in safe mode and it still will not open. Help!

Error
Joplin encountered a fatal error and could not continue.

To report the error, please copy the *entire content* of this page and post it on Joplin forum or GitHub.

If the error persists you may try to restart in safe mode, which will temporarily disable all plugins.

Message
Cannot read properties of undefined (reading 'key')

Version info
Joplin for Desktop

Copyright © 2016-2026 Laurent Cozic
Joplin 3.5.12 (prod, linux)

Device: linux, AMD Ryzen 7 8845HS w/ Radeon 780M Graphics
Client ID: 9959465eea794e60b1b95760c308ca91
Sync Version: 3
Profile Version: 49
Keychain Supported: No
Alternative instance ID: -

Revision: 449555c

Backup: 1.5.1
Combine notes: 1.2.3
Conflict Resolution: 1.2.3
Diff view: 0.3.1
Extra Markdown editor settings: 1.11.0
Favorites: 1.3.2
Freehand Drawing: 4.2.0
History Panel: 1.0.4
Hotfolder: 1.2.3
Import local CSS: 1.1.0
Inline tags: 1.3.0
Inline TODO: 2.0.5
Jarvis: 0.12.0
Joplin DDDot: 0.4.4
Kminder Mindmap: 0.8.7
Markmap: 1.9.1
Note list (Preview): 1.1.0
Note list and sidebar toggle buttons: 1.0.3
Note Rename: 1.0.0
Note Tabs: 1.4.0
...
Plugins
[
    {
        "id": "com.whatever.quick-links",
        "name": "Quick Links",
        "enabled": true,
        "version": "1.3.2"
    },
    {
        "id": "io.github.jackgruber.backup",
        "name": "Backup",
        "enabled": true,
        "version": "1.5.1"
    },
    {
        "id": "com.whatever.inline-tags",
        "name": "Inline tags",
        "enabled": true,
        "version": "1.3.0"
    },
    {
        "id": "joplin.plugin.templates",
        "name": "Templates",
        "enabled": true,
        "version": "3.0.0"
    },
    {
        "id": "joplin.plugin.space-indenter",
        "name": "Space Indenter",
        "enabled": true,
        "version": "0.2.6"
    },
    {
        "id": "joplin.plugin.note.tabs",
        "name": "Note Tabs",
        "enabled": true,
        "version": "1.4.0"
    },
    {
        "id": "io.github.jackgruber.combine-notes",
        "name": "Combine notes",
        "enabled": true,
        "version": "1.2.3"
    },
    {
        "id": "plugin.calebjohn.todo",
        "name": "Inline TODO",
        "enabled": true,
        "version": "2.0.5"
    },
    {
        "id": "joplin.plugin.benji.favorites",
        "name": "Favorites",
        "enabled": true,
        "version": "1.3.2"
    },
    {
        "id": "com.cuibonobo.NoteRename",
        "name": "Note Rename",
        "enabled": true,
        "version": "1.0.0"
    },
    {
        "id": "joplin-plugin-conflict-resolution",
        "name": "Conflict Resolution",
        "enabled": true,
        "version": "1.2.3"
    },
    {
        "id": "io.github.jackgruber.notelistpreview",
        "name": "Note list (Preview)",
        "enabled": true,
        "version": "1.1.0"
    },
    {
        "id": "de.fomin.markmap",
        "name": "Markmap",
        "enabled": false,
        "version": "1.9.1"
    },
    {
        "id": "org.joplinapp.plugins.whitespacer",
        "name": "Whitespacer",
        "enabled": false,
        "version": "1.0.2"
    },
    {
        "id": "io.github.jackgruber.hotfolder",
        "name": "Hotfolder",
        "enabled": true,
        "version": "1.2.3"
    },
    {
        "id": "io.github.jackgruber.copytags",
        "name": "Tagging",
        "enabled": true,
        "version": "1.0.3"
    },
    {
        "id": "outline",
        "name": "Outline",
        "enabled": false,
        "version": "1.5.15"
    },
    {
        "id": "org.joplinapp.plugins.YesYouKan",
        "name": "YesYouKan",
        "enabled": true,
        "version": "1.1.3"
    },
    {
        "id": "calandra.kminder.joplin",
        "name": "Kminder Mindmap",
        "enabled": true,
        "version": "0.8.7"
    },
    {
        "id": "joplin.plugin.benji.persistentLayout",
        "name": "Persistent Editor Layout",
        "enabled": true,
        "version": "2.2.0"
    },
    {
        "id": "io.github.personalizedrefrigerator.diff-view",
        "name": "Diff view",
        "enabled": true,
        "version": "0.3.1"
    },
    {
        "id": "joplin.plugin.alondmnt.sticky-note",
        "name": "Resume Note",
        "enabled": true,
        "version": "0.4.2"
    },
    {
        "id": "io.github.personalizedrefrigerator.import-local-css",
        "name": "Import local CSS",
        "enabled": true,
        "version": "1.1.0"
    },
    {
        "id": "joplin.plugin.alondmnt.history-panel",
        "name": "History Panel",
        "enabled": true,
        "version": "1.0.4"
    },
    {
        "id": "io.github.personalizedrefrigerator.js-draw",
        "name": "Freehand Drawing",
        "enabled": true,
        "version": "4.2.0"
    },
    {
        "id": "joplin.plugin.alondmnt.jarvis",
        "name": "Jarvis",
        "enabled": false,
        "version": "0.12.0"
    },
    {
        "id": "org.joplinapp.plugins.ToggleSidebars",
        "name": "Note list and sidebar toggle buttons",
        "enabled": true,
        "version": "1.0.3"
    },
    {
        "id": "com.joshthor.export",
        "name": "Save Note as MD",
        "enabled": true,
        "version": "1.0.2"
    },
    {
        "id": "io.github.personalizedrefrigerator.codemirror6-settings",
        "name": "Extra Markdown editor settings",
        "enabled": true,
        "version": "1.11.0"
    },
    {
        "id": "net.rmusin.joplin-table-formatter",
        "name": "Table Formatter Plugin",
        "enabled": true,
        "version": "1.2.1"
    },
    {
        "id": "joplin-plugin-dddot",
        "name": "Joplin DDDot",
        "enabled": true,
        "version": "0.4.4"
    }
]
Stack trace
TypeError: Cannot read properties of undefined (reading 'key')
    at calculateChildrenSizes (file:///tmp/.mount_joplinA6BbCR/resources/app.asar/gui/ResizableLayout/utils/useLayoutItemSizes.ts:87:39)
    at calculateChildrenSizes (file:///tmp/.mount_joplinA6BbCR/resources/app.asar/gui/ResizableLayout/utils/useLayoutItemSizes.ts:115:25)
    at file:///tmp/.mount_joplinA6BbCR/resources/app.asar/gui/ResizableLayout/utils/useLayoutItemSizes.ts:151:11
    at mountMemo (file:///tmp/.mount_joplinA6BbCR/resources/app.asar/main-html.bundle.js:3910:9746)
    at Object.useMemo (file:///tmp/.mount_joplinA6BbCR/resources/app.asar/main-html.bundle.js:3910:15081)
    at useMemo (file:///tmp/.mount_joplinA6BbCR/resources/app.asar/main-html.bundle.js:3832:1158)
    at useLayoutItemSizes (file:///tmp/.mount_joplinA6BbCR/resources/app.asar/gui/ResizableLayout/utils/useLayoutItemSizes.ts:141:9)
    at ResizableLayout (file:///tmp/.mount_joplinA6BbCR/resources/app.asar/gui/ResizableLayout/ResizableLayout.tsx:162:16)
    at renderWithHooks (file:///tmp/.mount_joplinA6BbCR/resources/app.asar/main-html.bundle.js:3910:419)
    at mountIndeterminateComponent (file:///tmp/.mount_joplinA6BbCR/resources/app.asar/main-html.bundle.js:3926:11328)
Component stack

    at ResizableLayout (file:///tmp/.mount_joplinA6BbCR/resources/app.asar/main-html.bundle.js:4645:18336)
    at div
    at MainScreenComponent (file:///tmp/.mount_joplinA6BbCR/resources/app.asar/main-html.bundle.js:5652:491)
    at ConnectFunction (file:///tmp/.mount_joplinA6BbCR/resources/app.asar/main-html.bundle.js:3973:23763)
    at div
    at NavigatorComponent (file:///tmp/.mount_joplinA6BbCR/resources/app.asar/main-html.bundle.js:5867:2085)
    at ConnectFunction (file:///tmp/.mount_joplinA6BbCR/resources/app.asar/main-html.bundle.js:3973:23763)
    at PopupNotificationProvider (file:///tmp/.mount_joplinA6BbCR/resources/app.asar/main-html.bundle.js:4830:1202)
    at Py.ThemeProvider (file:///tmp/.mount_joplinA6BbCR/resources/app.asar/main-html.bundle.js:4450:264)
    at ae (file:///tmp/.mount_joplinA6BbCR/resources/app.asar/main-html.bundle.js:4435:2912)
    at RootComponent (file:///tmp/.mount_joplinA6BbCR/resources/app.asar/main-html.bundle.js:6427:62)
    at ConnectFunction (file:///tmp/.mount_joplinA6BbCR/resources/app.asar/main-html.bundle.js:3973:23763)
    at ErrorBoundary (file:///tmp/.mount_joplinA6BbCR/resources/app.asar/main-html.bundle.js:5397:24683)
    at Provider (file:///tmp/.mount_joplinA6BbCR/resources/app.asar/main-html.bundle.js:3977:1461)

Screenshots

Log file

log.txt (65.1 KB)

Looks like the same issue as here: Error loading app after update to 3.4.12 - #12 by shauneverson

Have a read through the posts for a suggested solution (editing settings.json)

Thanks. I searched for it, but that one did not pop up for me. Regardless… BAM! I am working again.

My layout is insanity again, but … it’s working. :slight_smile:
Thanks.

@laurent There is a bug … somewhere. :slight_smile:

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