Files saved into (server-side) read-only folders get deleted

[danimo]

⚠️ Before submitting, please verify the following: ⚠️

• This is a bug, not a question or a configuration issue.
• This issue is not already reported on Github (I have searched for it).
• Nextcloud Server and Desktop Client are up to date. See Server Maintenance and Release Schedule and Desktop Releases for supported versions.
• I agree to follow Nextcloud's Code of Conduct

Bug description

Files that are being moved to a folder that is read only on the server results in deletion of said files. This is highly unexpected.

It seems that this is a further regression, see #7797.

Steps to reproduce

1. from another account, share a read-only folder
2. with your normal account, add a file to the now present read-only folder (i.e. touch keepme.txt)
3. wait for the client to run a sync cycle
4. verify that the file has now been deleted, contrary to expectation

Expected behavior

At least, the files should not be touched at all.

Even better yet, the local folder should not be writable either, or a warning should be triggered that some files cannot be synced.

Which files are affected by this bug

any

Operating system

macOS

Which version of the operating system you are running.

15.7.5

Installation method

Official MacOS Installer

Nextcloud Server version

33.0.5

Nextcloud Desktop Client version

33.0.5

Did this occur after an update or on a clean installation?

Minor version update (i.e. 33.0.0 → 33.0.1)

Are you using the Nextcloud Server Encryption module?

No

Are you using an external user-backend?

• Default internal user-backend
• LDAP or Active Directory
• SSO - SAML
• Other

Additional info

This is reproducible on Windows and MacOS, probably also Linux.

[danimo]

Client log:

2026-06-02 16:32:02:614 [ info nextcloud.sync.engine /Volumes/builds/39648/macos-39648/src/libsync/syncengine.cpp:627 ]:	#### Discovery start ####################################################
2026-06-02 16:32:02:614 [ info nextcloud.sync.engine /Volumes/builds/39648/macos-39648/src/libsync/syncengine.cpp:628 ]:	Server "33.0.5.1" 
2026-06-02 16:32:02:614 [ info nextcloud.sync.discovery /Volumes/builds/39648/macos-39648/src/libsync/discovery.cpp:79 ]:	STARTING "" OCC::ProcessDirectoryJob::NormalQuery "" OCC::ProcessDirectoryJob::NormalQuery
2026-06-02 16:32:02:614 [ info nextcloud.sync.accessmanager /Volumes/builds/39648/macos-39648/src/libsync/accessmanager.cpp:72 ]:	6 "PROPFIND" "https://redacted.server.net/remote.php/dav/files/Molkentin_Daniel/" has X-Request-ID "3530e820-fec1-449f-894e-4cb81cc79d70"
2026-06-02 16:32:02:614 [ info nextcloud.sync.networkjob /Volumes/builds/39648/macos-39648/src/libsync/abstractnetworkjob.cpp:382 ]:	OCC::LsColJob created for "https://redacted.server.net" + "/" ""
2026-06-02 16:32:02:781 [ info nextcloud.sync.networkjob.lscol /Volumes/builds/39648/macos-39648/src/libsync/networkjobs.cpp:537 ]:	LSCOL of QUrl("https://redacted.server.net/remote.php/dav/files/Molkentin_Daniel/") FINISHED WITH STATUS "OK"
2026-06-02 16:32:02:795 [ info nextcloud.sync.discovery /Volumes/builds/39648/macos-39648/src/libsync/discovery.cpp:79 ]:	STARTING "3D-Designs" OCC::ProcessDirectoryJob::ParentNotChanged "3D-Designs" OCC::ProcessDirectoryJob::NormalQuery
...
2026-06-02 16:32:02:803 [ info nextcloud.sync.discovery /Volumes/builds/39648/macos-39648/src/libsync/discovery.cpp:1512 ]:	Not a move, no item in db with inode 306397917
2026-06-02 16:32:02:803 [ info nextcloud.sync.discovery /Volumes/builds/39648/macos-39648/src/libsync/discovery.cpp:1891 ]:	Processing "ReadOnly/keepme.txt" | (db/local/remote) | valid: false/true/db | mtime: 0/1780410720/0 | size: 0/0/0 | etag: ""//"" | checksum: ""//"" | perm: ""//"" | fileid: ""//"" | inode: 0/306397917/ | type: CSyncEnums::ItemTypeSkip/CSyncEnums::ItemTypeFile/CSyncEnums::ItemTypeFile | e2ee: false/false | e2eeMangledName: ""/"" | file lock: not locked// | file lock type: ""//"" | live photo: false//false | metadata missing: /false/
2026-06-02 16:32:02:803 [ info nextcloud.sync.discovery /Volumes/builds/39648/macos-39648/src/libsync/discovery.cpp:1892 ]:	discovered "ReadOnly/keepme.txt" CSyncEnums::CSYNC_INSTRUCTION_NEW OCC::SyncFileItem::Up CSyncEnums::ItemTypeFile
2026-06-02 16:32:02:803 [ warning nextcloud.sync.discovery /Volumes/builds/39648/macos-39648/src/libsync/discovery.cpp:2006 ]:	checkForPermission: Not allowed because you don't have permission to add files in that folder: "ReadOnly/keepme.txt"
2026-06-02 16:32:02:803 [ info nextcloud.sync.engine /Volumes/builds/39648/macos-39648/src/libsync/syncengine.cpp:820 ]:	#### Discovery end ####################################################  189 ms
2026-06-02 16:32:02:803 [ info nextcloud.sync.engine /Volumes/builds/39648/macos-39648/src/libsync/syncengine.cpp:1203 ]:	will delete invalid read-only folders: "ReadOnly/keepme.txt"
2026-06-02 16:32:02:803 [ info nextcloud.sync.engine /Volumes/builds/39648/macos-39648/src/libsync/syncengine.cpp:1076 ]:	#### Reconcile (aboutToPropagate) ####################################################  189 ms
2026-06-02 16:32:02:803 [ info nextcloud.sync.statustracker /Volumes/builds/39648/macos-39648/src/libsync/syncfilestatustracker.cpp:233 ]:	Investigating "ReadOnly/keepme.txt" OCC::SyncFileItem::NoStatus CSyncEnums::CSYNC_INSTRUCTION_IGNORE OCC::SyncFileItem::Up CSyncEnums::ItemTypeFile
2026-06-02 16:32:02:803 [ info nextcloud.sync.engine /Volumes/builds/39648/macos-39648/src/libsync/syncengine.cpp:1083 ]:	#### Reconcile (aboutToPropagate OK) ####################################################  189 ms
2026-06-02 16:32:02:804 [ info nextcloud.sync.engine /Volumes/builds/39648/macos-39648/src/libsync/syncengine.cpp:1121 ]:	#### Post-Reconcile end ####################################################  189 ms
2026-06-02 16:32:02:804 [ info nextcloud.gui.folder /Volumes/builds/39648/macos-39648/src/gui/folder.cpp:1318 ]:	#### Propagation start ####################################################
2026-06-02 16:32:02:804 [ info nextcloud.gui.application /Volumes/builds/39648/macos-39648/src/gui/owncloudgui.cpp:253 ]:	Sync state changed for folder  "https://redacted.server.net/remote.php/dav/files/Molkentin_Daniel/" :  "Sync running"
2026-06-02 16:32:02:807 [ info nextcloud.sync.propagator /Volumes/builds/39648/macos-39648-build/arm64/macos-clang-arm64/build/nextcloud-client/work/build/src/libsync/nextcloudsync_autogen/EWIEGA46WW/../../../../../../../../../../../macos-39648/src/libsync/owncloudpropagator.h:213 ]:	Starting CSyncEnums::CSYNC_INSTRUCTION_IGNORE propagation of "ReadOnly/keepme.txt" by OCC::PropagateIgnoreJob(0x6000029dc540)
2026-06-02 16:32:02:807 [ warning nextcloud.sync.propagator /Volumes/builds/39648/macos-39648/src/libsync/owncloudpropagator.cpp:280 ]:	Could not complete propagation of "ReadOnly/keepme.txt" by OCC::PropagateIgnoreJob(0x6000029dc540) with status OCC::SyncFileItem::FileIgnored and error: "Not allowed because you don't have permission to add files in that folder"
2026-06-02 16:32:02:807 [ warning nextcloud.gui.activity /Volumes/builds/39648/macos-39648/src/gui/tray/usermodel.cpp:1155 ]:	Item  "ReadOnly/keepme.txt"  retrieved resulted in  "Not allowed because you don't have permission to add files in that folder"
2026-06-02 16:32:02:807 [ info nextcloud.gui.activity /Volumes/builds/39648/macos-39648/src/gui/tray/usermodel.cpp:1101 ]:	Item  "ReadOnly/keepme.txt"  retrieved resulted in error  "Not allowed because you don't have permission to add files in that folder"
2026-06-02 16:32:02:812 [ info nextcloud.sync.engine /Volumes/builds/39648/macos-39648/src/libsync/syncengine.cpp:949 ]:	Sync run took  197 ms
2026-06-02 16:32:02:812 [ info nextcloud.gui.folder /Volumes/builds/39648/macos-39648/src/gui/folder.cpp:1325 ]:	Client version 33.0.5  Qt 6.10.2  SSL  OpenSSL 3.5.6 7 Apr 2026
2026-06-02 16:32:02:812 [ info nextcloud.gui.folder /Volumes/builds/39648/macos-39648/src/gui/folder.cpp:1334 ]:	SyncEngine finished without problem.
2026-06-02 16:32:02:812 [ info nextcloud.gui.folder /Volumes/builds/39648/macos-39648/src/gui/folder.cpp:488 ]:	Folder "" sync result:  OCC::SyncResult::SyncRunning
2026-06-02 16:32:02:812 [ info nextcloud.gui.application /Volumes/builds/39648/macos-39648/src/gui/owncloudgui.cpp:253 ]:	Sync state changed for folder  "https://redacted.server.net/remote.php/dav/files/Molkentin_Daniel/" :  "Success, some files were ignored."