I'm running Ubuntu 10.04 Server as a file server. It is on the Windows Active Directory Domain (2008 SBS) and has been working well for several years (migrated to new hardware and upgraded from 8.04 a few months ago). Clients were originally all Windows XP, but now there's more Macs (12 Snow Leopard, 2 Lion) than Windows (1 XP, 1 Vista, 2 Seven), which are all still using Samba for sharing.
Today some users are having issues with various Adobe products on Snow Leopard (Flash CS5 and Photoshop at least) crashing or missing parts when opening files directly from the network, but they are fine when copying the file to the Desktop and opening from there. I have not had these issues personally.
What is the best method to determine what is going on?