I wanted to check my log today for a conversation but when I opened up my MyDocuments\Games\Freelancer and got the DSAce.txt it was completely blank apart from "Freelancer started"
This happened to me once, I dont know what causes this, but I know how to fix it:
Open the Shortcut and remove the -logchat (and -logtime if you have it) from command line
Remove the DSAce.txt from MyDocuments
Run the game, join the server, then Quit
Re-add the -logchat (and -logtime if you want it) to command line
You'll get logged chat again!
Although someone might be able to give a more 'Technical' explanation on why it happens, but this was how I fixed mine. It didn't save the logs for 5 days (And I lost logs of a really nice RP I had :/) Then had to do this to fix it.
Yeah i noticed that it just fails when you launch FAM. So now I just have to force myself not to be lazy and actually click on the real FL shortcut I made.