Encrypting a partition of a removable flash drive with TrueCrypt volume results in creating a shadow copy of a TrueCrypt disk image with ".tc" extension.
Comments
Creating an encrypted partition is a process of writing file system on the removable drive, and thus activates shadowing mechanism.
Recommendations
It is not possible to deny shadowing of *.tc files using content-aware rules. There is only one way to avoid shadowing of TrueCrypt partitions: