When using Messages in OS X to chat with friends and colleagues, the program will save a record of your message contents, to then keep a history of your conversation that you can review at a later point. While immediate conversation messages may be on Apple’s servers and synchronize to your devices, once this is done they will be gone, so your device retains the history so you can browse and search it if needed.
With this being the case, you may find yourself wanting to remove or edit your message histories. While individual messages cannot be modified, there are a few options you have to manage them:
Clicking a message once will select it, and now just press the Delete key to remove it after confirming you wish to do so. This will remove the individual message from the Messages database on your computer, while retaining all other messages in the conversation. You can select multiple messages by holding the Command key when clicking, or select all in a range between two messages by clicking one and then holding the Shift key when clicking another. Again press delete to remove these messages.
2. Clear the entire transcript
You can click somewhere in your conversation history, and then press Command-A to select all messages. Now pressing delete will act on all of the messages. You can perform this same task by right-clicking in the messages history, and then choose the option to clear the chat transcript. Note that if you right-click a message itself, then this option will be in the View submenu. A similar approach to clearing a transcript history can be performed by right-clicking your contact’s name and choosing the option to delete the conversation.
3. Reset Messages
A final option for managing messages is to remove the databases that Messages uses to store and organize your transcripts. This approach will remove all messages from all conversations, so be sure you want to clear everything before doing this. Then go to the Finder, press and hold the Option key, and then choose “Library” from the Go menu. Now locate the folder called “Messages” and remove it. When you next launch Messages, the program will recreate this folder, but your message conversations will be gone.
The first two approaches to managing your transcripts are the more supported ones, but the last one may be used to fix any corruption in your Messages databases that could be causing garbled messages, improper organization of messages (such as randomly organized messages), or faults with the Messages program crashing.
How is Clearing the Entire Transcript different from clicking the X on the left side of the Messages window?
You get to keep the thread.
Would this affect the Messages on ios device which sync to the same icloud account? If this same message history is also stored on an iPhone, would this alos remove them message history thee?