.MENC File Extension

Encrypted file created by Windows mobile devices; typically found on removable media cards; contains an encrypted version of the original file and additional header information; enables secure file storage on external storage cards.

MENC files are named with the convention FILENAME.GUID.menc, where FILENAME is the original file name and GUID is a generated key that lets an encryption filter know whether or not it can decrypt the file.

NOTE: MENC files are designed to be decrypted by the device that created the file. Therefore, MENC files can be transferred to a PC using Windows ActiveSync or Windows Mobile Device Center, but it may not be possible to decrypt the file on the computer. Also, changing the GUID on a MENC file will disable the ability of the decryption program to properly decrypt the file.

To avoid encrypting files, go to Settings → System or Settings → Security on the Windows Mobile device and uncheck the box that says "Encrypt files placed on storage cards."