How to bypass macOS "Sandboxing" for Excel VBA scripts

Hi @Fenni Tambou 

According to Request access to multiple files | Microsoft Learn, this is expected behavior on macOS. 

Excel for Mac (2016 and later) runs in a sandboxed environment, which means VBA and FileSystemObject (FSO) cannot write outside of Excel’s container unless the user explicitly grants permission using GrantAccessToMultipleFiles. 

For scenarios such as unattended logging, the only reliable approach is to write files inside Excel’s sandbox container: 

• ~/Library/Containers/com.microsoft.Excel/Data 
• ~/Library/Group Containers/UBF8T346G9.Office 

Please read more at Sandbox | Mac Excel Automation.

Granting Excel Full Disk Access in macOS settings may help in certain cases, but this is not documented or supported by Microsoft. You can refer to excel - VB Macros for Office 2016 for Mac require Permissions every time they try to access a file!… 

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Sandboxing cannot be bypassed on Excel for Mac. VBA code is prevented by design from writing arbitrarily to the macOS file system outside locations the sandbox can access.

To avoid repeated “Permission Denied” errors and user prompts, adapt the macro to work with the supported sandbox mechanisms instead of trying to bypass them:

1. Use GrantAccessToMultipleFiles for external paths
   • Build an array of POSIX file paths for all log files or folders the macro needs.
   • Call GrantAccessToMultipleFiles(fileArray) once at startup.
   • If the user grants access, the permission is stored with the app and will not be requested again for those paths.
   • Example pattern in VBA:

          Dim ok As Boolean
          Dim files(1 To 1) As String
          
          files(1) = "/Users/username/Logs/mylog.txt"   ' POSIX path
          
          ok = GrantAccessToMultipleFiles(files)
          If Not ok Then
              MsgBox "Access to log folder was not granted. Logging disabled."
              Exit Sub
          End If
          
          ' Now use FSO/Open to write to the file
     

   • Ensure the paths are POSIX-style (e.g., /Users/...), not HFS-style.
2. Keep using FSO, but only after access is granted
   • The sandbox restriction is about file-system permission, not specifically about FSO.
   • Once GrantAccessToMultipleFiles has been approved for a given path, FSO operations to that path should succeed without further prompts.
3. Designate a fixed log location and get one-time consent
   • Choose a single folder for logs (for example, a folder under the user’s home directory).
   • Request access to that folder path via GrantAccessToMultipleFiles.
   • Reuse that folder for all logging so the user is not prompted for each new file.
4. Do not attempt to disable sandboxing
   • On Office for Mac, sandboxing is enforced by the OS and cannot be turned off for Excel.
   • The supported pattern is to request and cache access using GrantAccessToMultipleFiles.

If the macro also needs to interact with other macOS apps or the Finder (for example, to move or manage log files), use AppleScriptTask with an AppleScript placed under ~/Library/Application Scripts/com.microsoft.Excel/, as direct cross-app automation from VBA is also restricted by the sandbox.

References:

• Request access to multiple files
• Run an AppleScript with VB
• Permission denied (Error 70)