Now it works :D .
Much thanks.

https://tartarus.org/~simon/putty-snapshots/w32/puttygen.exe

The next release of WinSCP will include dev version of PuTTYgen.

1. Cypher, what you mean by that, I said :ssh-2.
In id_rsa file I found:
-----BEGIN RSA PRIVATE KEY-----
Proc-Type: 4,ENCRYPTED
DEK-Info: AES-128-CBC,<--32_chars_hex_value-->

<--25 lines of
64_chars_alpha-numerical_value-->
-----END RSA PRIVATE KEY-----

Was generated by $ ssh-k e y g e n -C 'My Name'
on one week old version of Cygwin.
( I had to insert the spaces above, because otherwise my post is rejected by your spam filter )

2. Can't find a link to dev build of PuTTYgen, please help.

So what cipher does your private-key use? Try using the development version of puttygen.

I'm now registered to the forum.
Just to enable email notification on this topic.

I have a SSH-2 key, generated by OpenSSH.
On importing the key via PuTTYgen I get the error:
Couldn't load private key (ciphers other than DES-EDE3-CBC not supported)

What can I do ?