%26 %3D %40 in filename

[behoyt]

I am trying to sync my Thunderbird emails using FTP to my cloud server.

Various special characters are represented as %xx in filenames in the
Thunderbird folders that show up converted to the characters they
represent on the server.
Example
On server:
!&!AAAAAAAAAAAYAAAAAAAAAMYhg1YdhGVBl3DmCwfkjtLCgAAAEAAAAA+ZgZohYN9NqALAeUdL3VkBAAAAAA==@freemail.hu.wdseml
In Windows folder:
!%26!AAAAAAAAAAAYAAAAAAAAAMYhg1YdhGVBl3DmCwfkjtLCgAAAEAAAAA%2BZgZohYN9NqALAeUdL3VkBAAAAAA%3D%3D%40freemail.hu

So FreeFileSync does not compare them as equal files.

How do I overcome this?

Bruce