Unable to modify the files/folders, do we need to handle anything special for macOS 26 (Tahoe) with Fuse 5.0.6?

[Kathiresan22]

Summary:
When attempting to rename or editing a file in Finder on macOS 26 (Tahoe) mounted with defer_permissions, allow_other, and auto_xattr.

• Terminal touch and write worked, but Finder aborts WRITE or RENAME request.
• Rename did not work in any of the case

Observed Behavior:

• Finder eventually shows “You don’t have permission to rename the file”.

What I’ve Tried:

• Mount options:defer_permissions, allow_other, auto_xattr, auto_cache
• Verified parent directory permissions (drwxr-xr-x) and cleared immutable flags.

Debug Evidence:

• Fuse with debug mode

unique: 9, opcode: RENAME (12), nodeid: 2, insize: 75, pid: 964
rename /My Files/debug.txt /My Files/debu.txt
   unique: 9, error: -13 (Permission denied), outsize: 16

Questions:

1. Are there additional mount options or FS attributes required to make Finder proceed with rename?
2. Is there a known workaround for Finder preflight checks on macOS 26?

[marius-cristian]

Hi,

How did you implement the rename?

I remember I had tons of problems, as High-Level apps, use Rename with this flag: RENAME_SWAP

see man rename

and this discussion:
#1027

I also had one on apple developer forum, but I lost it.

In short, if you use Mac Apps, on each save they call rename with swap flag, they expect the Inode to be the same, but the swap to happen.

Hope it helps.

[Kathiresan22]

Thanks for replying. It seems that not only on Tahoe, but also on Sequoia I’m facing the same issue with 5.0.6. It’s failing even before it reaches the rename handler implementation.

[marius-cristian]

What does the Access call return? How about the Getattr?
Have you tried using dtruss to trace the system call from Finder? It might provide more details into the exact calls that fail.

[marius-cristian]

When you use TextEdit on file myfile.txt I am confident it will create a folder: myfile.txt-sb<somecode>/myfile.txt and on each save it will call rename swap between myfile.txt and myfile.txt-sb<somecode>/myfile.tx

[Kathiresan22]

The issue occurred due to a change in the move callback method signature.

In version 4.8.3, the implementation was:

- (BOOL)moveItemAtPath:(NSString *)path 
                toPath:(NSString *)otherPath 
                 error:(NSError * _Nullable * _Nonnull)error 

In version 5.0.6, it was updated to:

- (BOOL)moveItemAtPath:(NSString *)path 
                toPath:(NSString *)otherPath 
               options:(GMUserFileSystemMoveOption)options 
                 error:(NSError * _Nullable * _Nonnull)error

If the new move callback is not implemented, renaming operations fail with a "Permission denied" error.

Implementing the updated method resolved the issue.

Thanks for the support!

[bfleischer]

I'm glad you found the issue. The old move method has been deprecated since the release of macFUSE 4.0 in 2020. The framework has been logging a deprecation warning every time you launched your file system for the past 5 years.