Edit: After half day, my wife’s Mac started having the same problem. I have then applied the solution that I found in the Apple
Encrypt Your USB Flash Drives, External USB Drives Or SD Cards
Mac operating systems solely hold the entire credit of opening gates towards the using of FileVault 2. There are several features which are performed by this application such providing Apple for full disk encryption. It is considered as an essential element of Mac operating units and is a very mush welcomed addition in the family. The program is so easy to use that it can be easily programmed by anyone to either perform an encryption onto the startup drive or to encrypt the USB thumb drive along with the SD cards.
Many people ask the question as to why the need for encrypting an SD card or thumb drives arises? The answer is, in fact, easy and simple. As both the devices are small, they are easily subjected to get lost. Now, if there is confidential data stored within it, any person who got hands on it can make wrong use of the data stored. If the device be encrypted, only the original owner of the device can use it and no one else can.
before we get started, one important point which is worth mentioning is that never perform this application on any of those devices which has the data you want to save as the USB thumb drive or the SD card will be completely erased. Still, if you want to perform such an act, create a backup of the entire data on a separate drive and then start the encryption process after which the stored data can be retrieved back into the drive.
The first step involved in the process is to insert the USB thumb drive or the SD card into the Mac system. Go to the Disk utility option located in the Applications/Utility folder in the startup drive and launch the application. From the drop down arrow, select the format type as Mac OS X Extended and then provide it a title. In case, no title is given, it will be saved as Untitled by default. Now click on the option of Erase for the purpose of completely removing the data and start the encryption of the selected device by using the application of FileVault 2. Before the drive is formatted, the program will prompt for a password. After the password is entered, the card or the drive get encrypted and is ready for the user to use it, but, with the following caveats in it:
- The application is now only compatible with Mac operating systems.
- The system is no longer in a mode of compatibility with the Windows operating system.
- The password which has been entered into the Disk Utility so as to use the drive is very important. In case, it gets lost, there is no other way to retrieve data stored in it and it will be considered as lost data.
Finalizing, there is one more thing to talk about the encryption process of FileVault 2. The application has also been formulated to work with external hard drives that are attached via the FireWire, Thunderbolt and the USB by the same steps of a normal encryption process.