Usually, this is related to drive speed. I’m not sure why you’re using ProResHQ with SD. It’s only recommended for grater than 1080×1920 resolutions like 2K and up. The data rate of HQ is high. If your drive is getting full or experiencing problems ro both, that could be what’s going on. Check the drive speed with AJA System Test and see if it’s enough to handle HQ.
John
MacPro 8-core 2.8GHz 8 GB RAM OS 10.5.8 QT7.6.4 Kona 3 Dual Cinema 23 ATI Radeon HD 3870, 24″ TV-Logic Monitor, ATTO ExpressSAS R380 RAID Adapter, PDE enclosure with 8-drive 6TB RAID 5
FCS 3 (FCP 7.0.1, Motion 4.0.1, Comp 3.5.1, DVDSP 4.2.2, Color 1.5.1)
Pro Tools HD w SYNC IO & 192 Digital I/O, Yamaha DM1000, Millennia Media HV-3C, Neumann U87, Schoeps Mk41 mics, Genelec Monitors, PrimaLT ISDN