Is there an alternative for TrueCrypt?
Encrypted Disk Images

The TrueCrypt pages suggest using an encrypted disk image.

FileVault

Apple provides drive level encryption through FileVault.


  With FileVault 2 you can encrypt the contents of your entire drive to
  help keep your data secure.
  
  FileVault 2 uses full disk, XTS-AES 128 encryption to help keep your
  data secure. Using FileVault 2, you can encrypt the contents of your
  entire drive.


Alternatives

Other alternatives are discussed at:


Hacker News, True Goodbye: ‘Using TrueCrypt Is Not Secure’
Windows Encrypted Virtual Hard Drive but not Bitlocker or Truecrypt? Where cross platform alternatives may be suggested.
A Swiss based TrueCrypt group has recently formed; they may provide ongoing support.


Why not trust TrueCrypt?

TrueCrypt is warning its users that it may contain unfixed security issues.


  WARNING: Using TrueCrypt is not secure as it may contain unfixed
  security issues


The development of TrueCrypt has stopped and thus any newly found bugs may not be fixed:


  The development of TrueCrypt was ended in 5/2014 after Microsoft
  terminated support of Windows XP. Windows 8/7/Vista and later offer
  integrated support for encrypted disks and virtual disk images. Such
  integrated support is also available on other platforms (click here
  for more information). You should migrate any data encrypted by
  TrueCrypt to encrypted disks or virtual disk images supported on your
  platform.