If it's only with DropBox, maybe try some other solutions ?
I believe maybe the problem is on the combo of Apple and DB, as i did earlier have a guy that run TC for win in a MAC/ Parallell system and he also have a lot of crash/ problems until he changed to PC instead of MAC.
And he did use sync function in DB in both cases.
V18, V19, V20, V21, 2015 Pro. Platinum
Deluxe V20, V21, 2015
Windows 10 Home Premium 64 bit, 32 GB
NVIDIA Geforce GTX 780m, 1 GB