The Basics
- Nextcloud Server version (e.g., 29.x.x):
32.0.6
- Operating system and version (e.g., Ubuntu 24.04):
Debian Trixie (Using X11, KDE Pasma 6)
- Is this the first time you’ve seen this error? (Yes / No):
Yes
- When did this problem seem to first start?
Since upgrading to 4.0.6
- Installation method (e.g. AlO, NCP, Bare Metal/Archive, etc.)
AIO
- Are you using CloudfIare, mod_security, or similar? (Yes / No)
No
Summary of the issue you are facing:
When trying to start Nextcloud Files (AppImage) I get the following error:
Failed to initialize instances shared memory: "QSharedMemory::handle: doesn't exist"
XIO: fatal IO error 17 (File exists) on X server ":0"
after 469 requests (469 known processed) with 0 events remaining.
Steps to replicate it (hint: details matter!):
- Try to start Nextcloud 4.0.6 AppImage
Important
Downgrading to 4.0.4 makes the app work again.
Log entries
Nextcloud
2026-02-28 14:06:09:290 [ info nextcloud.gui.application /home/user/src/gui/application.cpp:747 ]: ################## "Nextcloud" locale: "en_GB" ui_lang: QVariant(Invalid) version: "4.0.6 (build 36659)" os: "Debian GNU/Linux 13 (trixie)"
2026-02-28 14:06:09:290 [ info nextcloud.gui.application /home/user/src/gui/application.cpp:752 ]: Arguments: QList("/home/[REDACTED]/Applications/Nextcloud-4.0.6-x86_64_bce2f9f223c016d1f648a85382cd475a.AppImage")
2026-02-28 14:06:09:290 [ info nextcloud.gui.application /home/user/src/gui/application.cpp:1028 ]: System UI languages are: QList("en-Latn-GB", "en-GB", "en-Latn", "en")
2026-02-28 14:06:09:290 [ info nextcloud.gui.application /home/user/src/gui/application.cpp:1031 ]: selected application language: "en_Latn_GB"
2026-02-28 14:06:09:291 [ info nextcloud.gui.application /home/user/src/gui/application.cpp:1051 ]: Using "en_Latn_GB" translation
2026-02-28 14:06:09:291 [ info nextcloud.gui.application /home/user/src/gui/application.cpp:126 ]: This is not an upgrade/downgrade/migration. Proceed to read current application config file.
2026-02-28 14:06:09:291 [ warning nextcloud.gui.application /home/user/src/gui/application.cpp:329 ]: Config version migration was not possible.
2026-02-28 14:06:09:300 [ info nextcloud.gui.application /home/user/src/gui/application.cpp:377 ]: VFS suffix plugin is available
2026-02-28 14:06:09:301 [ info nextcloud.gui.socketapi /home/user/src/gui/socketapi/socketapi.cpp:300 ]: server started, listening at "/run/user/[REDACTED]/Nextcloud/socket"
2026-02-28 14:06:09:301 [ info nextcloud.gui.folder.manager /home/user/src/gui/folderman.cpp:68 ]: setting remote poll timer interval to 30000 msec
2026-02-28 14:06:09:301 [ info nextcloud.gui.account.manager /home/user/src/gui/accountmanager.cpp:164 ]: Checking for accounts versions.
2026-02-28 14:06:09:301 [ info nextcloud.gui.account.manager /home/user/src/gui/accountmanager.cpp:165 ]: Config accounts version: 13
2026-02-28 14:06:09:301 [ info nextcloud.gui.account.manager /home/user/src/gui/accountmanager.cpp:166 ]: Max accounts Version is set to: 13
2026-02-28 14:06:09:397 [ info nextcloud.gui.account.manager /home/user/src/gui/accountmanager.cpp:632 ]: Account for QUrl("[REDACTED]") using auth type "webflow"
2026-02-28 14:06:09:398 [ info nextcloud.sync.credentials.webflow /home/user/src/gui/creds/webflowcredentials.cpp:122 ]: Get QNAM
2026-02-28 14:06:09:407 [ info nextcloud.gui.account.manager /home/user/src/gui/accountmanager.cpp:692 ]: Restored: 0 unknown certs.
2026-02-28 14:06:09:574 [ info nextcloud.gui.folder.manager /home/user/src/gui/folderman.cpp:187 ]: Setup folders from settings file
2026-02-28 14:06:09:574 [ info nextcloud.gui.folder.manager /home/user/src/gui/folderman.cpp:390 ]: FolderDefinition::maxSettingsVersion: 13
2026-02-28 14:06:09:574 [ info nextcloud.gui.folder.manager /home/user/src/gui/folderman.cpp:390 ]: FolderDefinition::maxSettingsVersion: 13
2026-02-28 14:06:09:574 [ info nextcloud.gui.folder.manager /home/user/src/gui/folderman.cpp:390 ]: FolderDefinition::maxSettingsVersion: 13
2026-02-28 14:06:09:576 [ info nextcloud.sync.configfile /home/user/src/libsync/configfile.cpp:1282 ]: Adding user defined ignore list to csync: "/home/[REDACTED]/.config/Nextcloud/sync-exclude.lst"
2026-02-28 14:06:09:632 [ info nextcloud.sync.database /home/user/src/common/syncjournaldb.cpp:335 ]: sqlite3 version "3.50.4"
2026-02-28 14:06:09:632 [ info nextcloud.sync.database /home/user/src/common/syncjournaldb.cpp:347 ]: sqlite3 locking_mode= "exclusive"
2026-02-28 14:06:09:632 [ info nextcloud.sync.database /home/user/src/common/syncjournaldb.cpp:355 ]: sqlite3 journal_mode= "wal"
2026-02-28 14:06:09:632 [ info nextcloud.sync.database /home/user/src/common/syncjournaldb.cpp:377 ]: sqlite3 synchronous= "NORMAL"
2026-02-28 14:06:09:633 [ info nextcloud.gui.folder.manager /home/user/src/gui/folderman.cpp:1310 ]: Adding folder to Folder Map OCC::Folder(0x561783f30210) "1"
2026-02-28 14:06:11:224 [ warning nextcloud.gui.folder /home/user/src/gui/folder.cpp:1589 ]: Folder watcher for "/home/[REDACTED]/" became unreliable: "This problem usually happens when the inotify watches are exhausted. Check the FAQ for details."
2026-02-28 14:06:11:436 [ info nextcloud.gui.folderwatcher /home/user/src/gui/folderwatcher.cpp:141 ]: Permissions in file system for "/home/[REDACTED]/.nextcloudpermissions.log" works as expected
2026-02-28 14:06:11:436 [ info nextcloud.gui.folder.manager /home/user/src/gui/folderman.cpp:741 ]: Schedule folder "1" to sync!
2026-02-28 14:06:11:436 [ info nextcloud.gui.folder.manager /home/user/src/gui/folderman.cpp:754 ]: Folder is not ready to sync, not scheduled!
2026-02-28 14:06:11:437 [ warning nextcloud.gui.application /home/user/src/gui/application.cpp:539 ]: Account(s) setup result: OCC::AccountManager::AccountsRestoreSuccess
2026-02-28 14:06:11:437 [ warning nextcloud.gui.application /home/user/src/gui/application.cpp:540 ]: 1 folder(s) migrated
2026-02-28 14:06:11:437 [ warning nextcloud.gui.application /home/user/src/gui/application.cpp:541 ]: 1 account(s) migrated: "- [REDACTED]"
2026-02-28 14:06:11:451 [ info nextcloud.sync.clientproxy /home/user/src/libsync/clientproxy.cpp:96 ]: Set proxy configuration to use the preferred system proxy for http tcp connections
2026-02-28 14:06:11:451 [ warning qt.core.qobject.connect unknown:0 ]: QObject::connect(QNetworkInformation, OCC::Application): invalid nullptr parameter
2026-02-28 14:06:11:458 [ warning nextcloud.sync.configfile /home/user/src/libsync/configfile.cpp:711 ]: Default update channel is "stable"
2026-02-28 14:06:12:315 [ warning default unknown:0 ]: The X11 connection broke: No error (code 0)