I've been trying to troubleshoot random dropouts with Serato DJ and a DDJ-SX. Macbook Pro mid-2012. More specs at end of post...

Support has been unhelpful, they take days one end to reply and in fact, I think they've abandoned my ticket. The last thing I was instructed by them was to create a new database file, which I had earlier in the summer, I believe, by consolidating my music library to only tracks that were in my crates. This link they gave me suggests dragging all your tracks only but then your crates would all be gone after the new database. Can one follow this procedure by dragging all of your crates to the 'Backup All' crate? support.serato.com

The weird thing about my support ticket is they initially said it could only be one of a few things. But they didn't tell me what those things could be. When I asked, they said it's complicated etc and that I needed to follow their suggestion first, test and then report back in order to hear what's next. The problem with this is, the dropouts only occur over a 4-6 hour set and I can't just DJ all day to see if it will happen again. I just want to do whatever I can to make this problem stop. It's really affecting my gigs when the music just stops for 3-6 seconds in the middle of a big tune! I don't see why they have to only tell me their tips in this slow, drawn out drip support.

So far, I've reformatted my Macbook with a clean wipe, reinstalled only Serato and setup everything as per their specs. Large usb buffer setting (10), no wifi or bluetooth when performing and all that. Still have the dropouts. Swapped usb cables of course, same issue. Could it be the DDJ-SX? When the problem occurs I don't see any usb warnings and the music appears to be playing, it comes back in where the song would have been if kept playing. Any ideas, solutions to the vexing issue?

MB Pro 13 inch, mid 2012, OS 10.11
Processor: 2.9 Ghz Intel Core i7
Memory 8 GB 1600 Mhz DDR3
Graphics: Intel HD Graphics 4000 1536 MB
External HD: WD My Passport USB 3
Serato: 1.9.6
Pioneer DDJ-SX