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Shake error: Disk cache locked

When Shake restarts after a crash, you may be familiar with this message:



But what does it mean and which option should you choose?

Shake has two caches - one that stores whole frames and another that stores tiles (segments of frames). These two caches work together to speed up rendering and the responsiveness of the interface. These caches operate both in memory and on the disk. Although they are not quite the same, think of them as a similar concept to Final Cut Pro's render files.

When you quit Shake, it copies the memory cache to the disk cache (if you've ever wondered why there's a delay when you quit Shake, that's the reason) and leaves it on disk so that it is there the next time you open Shake.

If your machine crashes or you force-quit the application, this process does not take place and the disk cache becomes invalid. You are given the choice of moving the old cache to a temporary location and creating a new one (recommended) or disabling caching altogether (recommended only if you are running two copies of Shake on the same machine). Copying the cache to a temporary location allows you to salvage any required information from it before trashing it.

Speaking of which, if Shake crashes a lot, you will end up with lots of temporary caches cluttering up space (mine took up over 1 GB). Every so often, you should go to /var/tmp/Shake and delete all of the folders marked TempCache. Do not delete the one marked cache, as that is your current cache. Note that you will probably not be able to browse to the /var folder because it is hidden so it is recommended to go to the Go menu in the Finder and select Go to Folder and type the path in.

So in summary, when you get that message, you are recommended to click Ok and delete the temporary cache later. You might experience a loss of speed and responsiveness (most likely not noticeable) but Shake will gradually speed up as the cache is refilled with data over time.

P.S. I really should write more Shake articles. If you have any suggestions as to what you'd like to see, please let me know.