Finder window pops up every time Time Machine makes a backup

I have configured a shiny new Time Capsule a few days ago. It runs firmware 7.7.1 and my Mac is on 10.8.4.

The Time Capsule works perfectly so far, except that every time Time Machine makes a backup, a Finder window showing the contents of the “Time Machine Backups” volume pops up (see screenshot). This gets especially annoying with hourly backups. I backed up with an external hard drive before and did not have that issue as far as i know. How can I stop Time Machine/Finder from opening up that window every time?

Solution 1:

I solved it by running

sudo defaults write com.apple.frameworks.diskimages auto-open-rw-root -bool false

Source: https://superuser.com/questions/584237/make-time-machine-stop-opening-a-new-window-when-backing-up