In the wake of PowerBook Display issues and Panther Firewire issues, some customers are also being affected by the adoption of FileVault - Apple's on-the-fly file encryption.
According to this article, the problem appears when FileVault asks to "reclaim lost disk space in the encrypted directory".
After this, data from Safari, Address Book, the Dock, Mail and Keychain can be affected, leading to an unstable system. Apple reports being aware of the issues and is investigating reports.
Related: Ongoing thread at Apple's Discussion Forum.
