Which type of acquisition would generally not be recommended for an encrypted drive?

Logical acquisition is generally not recommended for an encrypted drive because it only copies the files and directories visible to the operating system at the time of acquisition. If the drive is encrypted, the operating system may not have access to the decrypted data, resulting in an incomplete image that misses critical information.

In contrast, bit-by-bit acquisition captures every single bit of data on the drive, including hidden, deleted files and unallocated space, which is essential for forensic investigations. It preserves the entire state of the drive, maintaining integrity and enabling investigators to analyze all data, even encrypted segments, if the appropriate decryption keys or methods are available.

File system acquisition focuses on the logical structure of the data but does not necessarily capture all data on the drive, making it inadequate for encrypted drives as well. Clone acquisition also involves creating a bit-for-bit copy of the drive while maintaining its original structure, similar to bit-by-bit acquisition, making it suitable for encrypted data if the right decryption methods are applied. Thus, logical acquisition, which does not encompass all data and only accesses files that are visible and accessible, is the least appropriate choice when dealing with encrypted drives.