http://bugzilla.suse.com/show_bug.cgi?id=909718 --- Comment #7 from Dominique Leuenberger <dimstar@opensuse.org> --- (In reply to Michael Schröder from comment #6)

My 2 cents:

coolo says it's because some postinstall script starts gpg-agent, which leads to the device being busy and a failed umount.

I think here it's rather the interaction with libzypp and gpg and gpg firing up gpg-agent for itself -- You are receiving this mail because: You are on the CC list for the bug.