I used to access the chat.db in this directory via sqlite3 but this obviously no longer works; in addition the directory is no longer accessible as can seen below: $ cd ~/Library/Messages $ pwd /Users/moshe/Library/Messages $ ls ls: .: Operation not permitted*
macOS Mojave now protects certain locations. You can allow Terminal (and other apps) to access these locations by going to System Preferences > Security & Privacy > Privacy > Full Disk Access
.
See “Full Disk Access” in Privacy Preferences help.