
Though OS X’s disk utility is fully capable of encrypting files, there are some instances where you may need to share encrypted volumes across platforms. In this situation truecrypt is a compelling solution.
The problem with truecrypt on a mac, however, is that the encrypted volumes must be manually mounted before you can utilize them. This amounts to opening truecrypt, locating each volume, and mounting each disk every time you login. If you’ve got half a dozen volumes scattered about, truecrypt becomes more of a obstacle and less a tool.
Fortunately, there is a very straightforward way of automatically prompting you for each of your encrypted drives’ passwords and mounting the disks at login. All that is required is some very simple automator magic. Step through this process and all you’ll have to worry about is remembering the passwords you’ve used for each of your encrypted volumes.
1 ) Prerequisites.
Obviously you’ll need to install truecrypt. Automator is installed on every mac by default, so you should already have that available.
You’ll need to find the path to the trucrypt application (the default is /Applications/TrueCrypt.app )
You’ll also need the paths to each of your encrypted volumes. In this example my volumes are at /Users/James/Installs/test and /Users/James/Installs/test2.
2 ) Open up automator (the icon looks like a robot holding a chrome pipe) and choose the “Application” template.

3 ) Find the “Run Shell Script” action (by typing “run shell script” in the search field), and then drag it to the main workflow.

4 ) In the Run Shell Script Action, add the following lines, substituting /Users/James/Installs/test and /Users/James/Installs/test2 with the location of your encrypted volumes.
/Applications/TrueCrypt.app/Contents/MacOS/TrueCrypt –mount /Users/James/Installs/test
/Applications/TrueCrypt.app/Contents/MacOS/TrueCrypt –mount /Users/James/Installs/test2

5 ) Save the workflow as an application.

6 ) Open “System Preferences” and select “Accounts”.

7 ) In the accounts window select your account in the left table, select “Login Items” and then click the “+” button. A window will pop up and from this you will need to locate the application you just created in automator.

8 ) After you’ve selected your application, it should appear in the list of items under “These items will open automatically when you log in”.

9 ) That’s it! Test it out, and if you did everything correctly you’ll be prompted for passwords to each of your encrypted volumes the next time you log in.
