"operation not allowed" when accessing network drive

I get an "operation not allowed" error in Matlab (only in Matlab) on MacOS when trying to access network-mounted RAID drive

Desktop Mac (1) running Macos 26.3.1, has network-mounted a USB-C external RAID drive connected to older desktop Mac (2) running 15.7.4.

I can view, edit, save etc. files on the (remote) RAID system using terminal windows on (1), using Finder, TextEdit, etc.. But attempting to access folders or files from within Matlab R2024b returns the error "operation not allowed".

Both systems (1) & (2) have Matlab given "full disk access" in Settings>Privacy&Security>FullDiskAccess. Both systems have user given read&write access for shared network drive in Finder>Get_Info, in Unix permissions, and in Settings>Sharing>File_Sharing.

Matlab on (2) can read & write files on the (locally-attached) RAID drive. The problem is only when trying to access the RAID drive from within in Matlab on (1).

smbd also has full disk access (as is clear since terminal and other apps can read & write RAID drive over network connection).

Any suggestions would be appreciated.

[Walter Roberson]

I do not know what causes this, but a small number of people have reported similar problems.

It is common that the problem involves updating files, but not copying in complete files (to local drives), and sometimes not copying out (to networked drive) complete files.