Following table shows known issues of interoperability with various SFTP servers. It includes both problems of the servers or known problems (typically fixed) of WinSCP that emerge with particular server only. It also includes special (even proprietary) features of some servers that WinSCP can use.

Workarounds for bugs of major SFTP servers can be configured on SFTP tab of Login dialog.

Server Issue Solution / Use
OpenSSH Supports SFTP version 3 only.
Cannot handle SFTP packets larger than 256 KiB, but due to support for SFTP version 3 only, it cannot report the limitation. WinSCP automatically limits size of SFTP packet to 256 KiB when connected to OpenSSH SFTP server.
Reverses order of symlink command arguments (SSH_FXP_SYMLINK request). WinSCP automatically reverses the order too, when connected to OpenSSH SFTP server.
Misinterprets file timestamps prior to 1970. WinSCP automatically interprets the timestamps in the same incorrect way when connected to OpenSSH SFTP server.
Cannot set special permissions. User can issue remote_command to set these permissions.
Cannot set special permissions. User can issue remote command to set these permissions.
VShell Windows version does not have Unix-like behaviour. WinSCP can handle that, but if version 4 or newer of SFTP protocol is used only.
Provides file attributes (SSH_FILEXFER_ATTR_BITS) with SFTP version 4, when it is allowed since version 5 only. WinSCP can handle that.
Incorrectly encodes list of supported SFTP versions. WinSCP can handle that.
Windows version does not provide owner/group in directory listing. WinSCP can request them explicitly before showing Properties dialog.
Sun SSH See OpenSSH.
FTPshell Does not support reading of file attributes (SSH_FXP_LSTAT request). WinSCP uses this also to check existence of directory before entering it. To allow user to enter to directory on FTPshell server, WinSCP automatically fall backs to checking the existence by reading directory content. This in turn forbids used to enter traverse-only directories (with permissions 110).
MultiNet For SFTP version 4, it indicates presence of UID/GUI in directory listing, but actually it does not include them. These attributes are not allowed for SFTP version 4 and newer, so WinSCP ignores the indication.
Foxit WAC server Does not use UTF-8 encoding for SFTP version 4 and newer. WinSCP does not expect UTF-8 encoding when connected to Foxit WAC server.
Titan FTP server Incorrectly encodes the filenames to UTF-8. Force SFTP version 3 either on server or client side to avoid UTF-8 encoding.
Incorrectly encodes server capabilities packet (supported2 extension). Force SFTP version 4 or lower either on server or client side to avoid the server provide the incorrect packet.
CoreFTP server Violates SFTP protocol in response to changing file properties. Turn off setting file properties (e.g. in transfer settings).