Large log files being created by scheduled defrag?

I am running Defraggler on a Server 2008R2 box. I have set it up to run scheduled defrags on Sundays. I used the GUI interface to do this, and it created a standard looking Task for it that executes this:

C:\Program Files\Defraggler\df64.exe "C:" /ts /user "Administrator" /appPath "C:\Program Files\Defraggler"

It seems to work well. However, today I happened to look in the Defraggler folder and found that there are large log files that seem to get created every time the scheduled task runs. They look like this:

df64.exe.[2_15_742][2015-02-22_10-21].txt

Why are these being created? They range anywhere from 5MB to 40MB in size (so I've got like 1.5GB of them total).

Do scheduled task versions of Defraggler always create these? Or only when there is an error or other problem?

I'm trying to determine if I can just ignore/delete them. Or if they mean something more (i.e. a problem) that I should look into.

- John...

df64.exe.[2_15_742][2015-02-22_10-21].txt

all of this with [2_15] [2_16] [2_17] --> the intended leftovers of the predecessors of Defraggler 2.18

the date is currently...

have you installed version 2.18?

Um, yes, I noticed there is a newer version and have upgraded to it now.

Are you saying that this is a KNOWN ISSUE with v2.15 through v2.17 then? Or are you just ignoring the issue because I happen to not be running the latest version?

I have since upgraded and the scheduled weekly scan will run soon and I'll see if it does it again. But I am fairly certain that it WILL happen again. Which leads us back to my original question/issue.

- John...

Or are you just ignoring the issue because I happen to not be running the latest version?
Yes, but 'ignoring' isn't really correct. It is not possible to see if a reported bug exists in a current version and thus needs a fix if it is reported from a lesser version.