Hi,

I'm using a Lowrance HDS Gen 3 and recording in SL3 format. I know that Reefmaster 2.0 creates its own smaller version of each log file I import, my question is do we lose any functionality by then deleting the much larger original Lowrance file? I seem to remember that in the past when I tried this I think I lost sonar/sidescan data but when I tried again this morning everything seemed to still work as expected?

Just wanted to check before I go through and delete all the old huge files I have, I'm down to my last 60GB on my Reefmaster laptop so it would be a great help.

ReefMaster doesn't need the original log files once it has created its own .idx file. You will still get access to all sonar viewer and sidescan features.
However, I wouldn't delete any of your original logs, as you never know when you might need them. It is possible that ReefMaster could be able to extract more information from them in the future, or other applications might be able to use them. By deleting your original logs you leave yourself with data in a proprietary format that can only be loaded into one application: ReefMaster. I would never trust my own data in this way with another application and can't recommend that you do it with ours.
What you could do is archive your log files somewhere. E.g. zip them up (you'll get a decent compression ratio on raw slg/2/3 files) and put them on some external storage such as a hard drive or USB thumb drive/SD card.