I was trying to connect to my Ubuntu server using SSH private key. For that I already converted my id_rsa file from ~/.ssh directory to a ppk file using PuTTYgen, but after loading my .ppk key I get below error:

Unable to load key file "F:\ubuntu.ppk" (Putty key format too new)

Solution 1 : Download the latest version of Putty

Usually the root cause is you are using a newer version of PuTTYgen than the version of PuTTY. So you can download the latest version of Putty


Solution 2 : Re-export your private key to version 2 of ppk using puttygen

  • Open your puttygen , click Key then Parameters for saving key files...



  • Select PPK file version : 2



  • load your ssh private key again , then save as ppk file

Conclusion

Now issue should be fixed ,no “Putty key format too new” error again.