500 MACB not understood


  • CuteFTP Mac all versions


The following command and error appear in the transfer log:


500 MACB not understood


CuteFTP Mac has the ability to transfer files in three different modes: ASCII, Binary, and MacBinary. By default, CuteFTP Mac will automatically choose the best transfer mode to use. Most Unix or Windows servers do not support MacBinary.

As part of the transfer process, CuteFTP needs to determine whether or not the remote server will support the MacBinary mode. To do so, CuteFTP issues the MACB ENABLE command to the remote server. 

  • If the remote server responds affirmatively, then the MacBinary mode is used to make any transfer.
  • If the remote server does not support MacBinary, then it will respond that the MACB ENABLE command was not understood.

CuteFTP interprets the response accordingly and uses the appropriate mode.


This error can be ignored. It is used for informational purposes only.

To change your transfer preferences

  1. Click CuteFTP Mac Preferences > Transfer Preferences.
  2. In the Transfer method area, specify whether CuteFTP Mac should automatically detect the transfer mode based upon the file type or force a particular mode, such as binary, ASCII, or MacBinary.
  3. In the Use binary mode when transferring ASCII files between UNIX hosts area, specify whether CuteFTP Mac should ignore the file type when transferring between UNIX hosts, always transferring in binary (the only mode UNIX hosts support).