TrueCrypt is undoubtedly stable, but it is getting rather long in the tooth. For example, TrueCrypt can't encrypt the system drive if your computer uses UEFI a

TrueCrypt is undoubtedly stable, but it is getting rather long in the tooth. For example, TrueCrypt can't encrypt the system drive if your computer uses UEFI and/or your boot drive has a GPT parition table. This is a major nuisance since nearly all new PCs have UEFI enabled by default. But TrueCrypt development has all but stalled for the last couple of years, and now there's zero hope of ever getting UEFI support.