I have a friend with G5 Mac desktop with 10.3.9/QT 7.5 and Toast 7.1.3. For a long time now, he has been a happy camper with this set up. But about a month ago, Toast started disappearing during the encoding phase of burning a DVD. It just disappears then reappears, empty. I have run Applejack, Tech Tools Pro and Disk Warrior, as well as upgrade QT to 7.5 (from some 7.1 version, I believe) so far and that has helped. He now only has this problem when he tries to burn a disk with large files of mixed origin: specifically, for example, when he tries to burn a DVD made from a 600 meg .avi and a 600 meg .mpg. Toast always will encode the .avi, then disappear when it has to deal with the .mpg.

What could be causing this, especially after such a long time (a couple of years, I believe) of happy DVD burning?

I don't know. Have you tried trashing the Toast plist and prefs files from the User>Library>Preferences folder and relaunching Toast? Does it help if Never Re-encode is selected in the custom encoder settings window for any mpeg files that already meet the video DVD spec?

Thanks, tsantee. I will try those things and get back to you. By the way, do you know how Toast and QT interact, especially during encoding?

I don't know the inner workings of Toast. I'm pretty sure Toast uses QuickTime for reading certain video files but uses its own encoder for MPEG 2 encoding.

You are, in fact, right. I have it on good authority that Toast uses QT to decode the files into raw DV. Then Toast encodes it into MPEG 2 with a built in encoder. I just found out a little earlier today.

Well, it took me long enough (work has been pretty taxing), but I have some more information. First, I have a section of the Toast crash report:

Exception: EXC_BAD_ACCESS (0x0001)
Codes: KERN_PROTECTION_FAILURE (0x0002) at 0x00010004

Thread 0 Crashed:
0 libSystem.B.dylib 0x90001f40 szone_calloc + 0xe4
1 libSystem.B.dylib 0x90002888 malloc_zone_calloc + 0xc4
2 libSystem.B.dylib 0x90003258 calloc + 0x4c

Do you know what libSystem.B.dylib is?

I know you've done a lot of diagnosis but I suggest downloading and running Rember to do a much more extensive memory test than TechTool can do.