Please read the FAQ (link below), particularly the topic on common Eraser problems, where this is covered in detail. Also, upgrade to the latest service release (18.104.22.1683), which, I believe, is less prone to this problem.
The problem, when it occurs, is intermittent. Your best option is to upgrade to version 22.214.171.1243, on which, during my own testing, I have not seen this problem (and which certainly fixes known related issues)
6.0.8 has just been released, and unfortunately problems with installing it over 6.0.7. have been reported. I suggest that you uninstall 6.0.7. and delete the Task List file (details in the FAQ) before installing 6.0.8.