Installer crashed with OSError: [Errno 17] File exists: '/target/opt' while upgrading

[Michael Geselbracht]

I tried to upgrade from 11.04 to 11.10 using the update-manager. Then the process stopped for some reason. The screen was black and I could not switch to a text console. After a restart I tried to resume the upgrade from an installation USB stick when this error occured.
I have chosen the "Update 11.10 -> 11.10" option.

ProblemType: Bug
DistroRelease: Ubuntu 11.10
Package: ubiquity 2.8.7
ProcVersionSignature: Ubuntu 3.0.0-12.20-generic 3.0.4
Uname: Linux 3.0.0-12-generic i686
ApportVersion: 1.23-0ubuntu3
Architecture: i386
CasperVersion: 1.287
Date: Sat Oct 15 02:05:32 2011
LiveMediaBuild: Ubuntu 11.10 "Oneiric Ocelot" - Release i386 (20111012)
ProcEnviron:
 LANGUAGE=de_DE.UTF-8
 PATH=(custom, no user)
 LANG=de_DE.UTF-8
SourcePackage: ubiquity
UpgradeStatus: No upgrade log present (probably fresh install)

[Robert Roth (evfool)]

Exception during installation:
Traceback (most recent call last):
File "/usr/share/ubiquity/install.py", line 656, in <module>
     install.run()
File "/usr/share/ubiquity/install.py", line 130, in run
     self.copy_all()
File "/usr/share/ubiquity/install.py", line 408, in copy_all
     os.mkdir(targetpath, mode)
OSError: [Errno 17] File exists: '/target/opt'

[Colin Watson (cjwatson)]

Thanks for your report. This looks like another instance of bug 891711.