To finish the installation, a window appears saying an unexpected error.

[miguel]

Jun 03 23:02:06 ubuntu subiquity_log.3757[8613]: curtin.util.ProcessExecutionError: Unexpected error while running command.
Jun 03 23:02:06 ubuntu subiquity_log.3757[8613]: Command: ['rsync', '-aXHAS', '--one-file-system', '/tmp/tmpx0mbeqlw/mount/', '.']
Jun 03 23:02:06 ubuntu subiquity_log.3757[8613]: Exit code: 23
Jun 03 23:02:06 ubuntu subiquity_log.3757[8613]: Reason: -
Jun 03 23:02:06 ubuntu subiquity_log.3757[8613]: Stdout: ''
Jun 03 23:02:06 ubuntu subiquity_log.3757[8613]: Stderr: ''
Jun 03 23:02:06 ubuntu subiquity_log.3757[8613]: Unexpected error while running command.
Jun 03 23:02:06 ubuntu subiquity_log.3757[8613]: Command: ['rsync', '-aXHAS', '--one-file-system', '/tmp/tmpx0mbeqlw/mount/', '.']
Jun 03 23:02:06 ubuntu subiquity_log.3757[8613]: Exit code: 23
Jun 03 23:02:06 ubuntu subiquity_log.3757[8613]: Reason: -
Jun 03 23:02:06 ubuntu subiquity_log.3757[8613]: Stdout: ''
Jun 03 23:02:06 ubuntu subiquity_log.3757[8613]: Stderr: ''
Jun 03 23:02:06 ubuntu subiquity_log.3757[8613]:
Jun 03 23:02:06 ubuntu subiquity_log.3757[8613]: Stderr: ''
Jun 03 23:02:06 ubuntu subiquity_event.3757[3757]: executing curtin install extract step
Jun 03 23:02:06 ubuntu subiquity_event.3757[3757]: installing system
Jun 03 23:02:06 ubuntu subiquity_event.3757[3757]:
Jun 03 23:02:06 ubuntu subiquity_event.3757[3757]: curtin command install

[Sebastien Bacher (seb128)]

Thank you for your bug report Could you add the logs from/var/log/installer after getting the problem?

The log extract here doesn't include the actual error but it seems the rsync command failed which is usually sign of a corrupted download or a disk error, could you check the media you are using for installation or maybe try another one?