XnView Software

You are right, this way the old sff plugin still works in a 32 bit environment. Thank you very much!

Thank you for your prompt response.
I installed the 32bit version of XnViewMP in Windows 10 Pro 64-bit, and it behaves the same as the 64bit version. Therefore, it seems there is no sff support at all in XnViewMP yet.

I tried XnView Classic in Windows and the sff files can be viewed. However, with a 64-bit version of XnViewMP on a Windows system, I have the same problem that the files cannot be opened. I have added an example file for testing.
Thanks again for your help.

Thank you for your answer. On my Mac I found this under Preferences ... > General| General tab -- Show all graphics formats and it is already enabled. Any other ideas?

I'd like to view sff-files with XnViewMP Version 0.76.1 x64 (Oct 26 2015) on an iMac Retina 5k, OS X El Capitan Version 10.11.3.
Under Formats it is stated Structured Fax Format Extension sff Read is supported. However, I get "File can't be loaded!" when I doubleclick on it. What gives?