Steps to reproduce: 1. Select known or unknown disto image. 2. Proceed with checksum verification or confirm 'Could not verify as a known distro image' dialog. 3. Press 'Write' button. 4. Remove USB drive from system. 5. Press 'Clear Disk and Write Image' button. Actual result: Program crashes. Expected result: Closing all possible popup confirmation dialogs and displaying of warning popup window about inability to write on selected device - immediately after removal of previously selected USB drive. There can be possible case when user not fully inserted the USB device or he has glitchy port or something.
Also warning popup window about inability to write on selected device can contain 'Retry' button with functionality to resume writing session.
Sorry, missed that one - https://bugs.kde.org/show_bug.cgi?id=382951 is duplicate of this bug.