Distribution Upgrade to 15.04 frozen during installation

[diagoras]

I was upgrading Kubuntu from 14.10 to 15.04 with the "Distribution Upgrade" GUI and it froze mid-installation (this occurred after the downloading was complete, it's not using my processor). The GUI is now just a blank grey box and I'm currently download the .iso for Kubuntu 15.04. I've backed up my files.
Is it advisable to forcibly terminate Distribution Upgrade and then restart it?
Is there anyway that I can reverse and/or cancel the changes that Distribution Upgrade has made so that I can try with the .iso?
Any other recommendations?

Thank you for your time.

[mannenrok]

Hi there,
There are a lot of issues with 15.04. I also have bad experiences with this upgrade. I advice you, at least for the time being, to use an LTS (14.04) version. It's not that modern but in stability its the best choice.
Henk

[diagoras]

End Result

Thank you for your reply. I eventually had to reinstall Kubuntu but fortunately it was stable enough .during the failed upgrade that I was able to back up all of my files (wow!).