I'm attaching my debug log as requested by the pop-up which also notified me that MyDefrag had crashed.
Thanks for posting the logfiles, I appreciate it. The debug logfile does not show a crash, I am guessing that it was overwritten by a later run. But don't bother making a new debug logfile, there is a known bug in the screensaver that causes it to occasionally crash. Will be fixed in the next version.
By the way, when I registered with this forum a few minutes ago, I got the following error message:
It's your email address. The forum delivers the welcome email immediately, but if your mailserver is down, or very slow, then it causes the timeout.
So I'm very suspicious of the specification of or invocation of a non-default secondary screensaver.
No, the problem is not caused by the alternate screensaver.