Update Animation Cache resulted in Blender screen inside Window border covered with half-transparent white (usually sign of a program freezing in Windows 7), appearing to freeze for hours, then filling disk until zero disk space. After doing a search I realized it was creating bphys files. I deleted the bphys files & it made more. Problem was repeatable. I determined that update animation cache was baking smoke, & that my smoke detail settings were too high (200+MB for each frame after the first few hundred, & filling over 50GB of free space eventually). I terminated blender.exe, opened my file again, then in Outliner I hid the smoke domain object from Realtime & Render. I hit update animation cache & the problem went away.
- To Do
This is quite silly but it's unfortunately a limitation of our dependency graph. In principle anything in the scene, even physics simulations, can influence the final cached sound. Currently Blender can only update the entire scene, it's not possible to update just the parts that sound needs.
There's plans to improve the dependency graph, but this is currently not considered a bug.