How do I reset iMessage in OSX 10.13.3 (High Sierra)?

Hi,

Deleting the .plist linked to the app may help.

These are in your User Folder (the Little House icon) and then Library. ) often written as ~/Library

However this Library is normally invisible.

Open a Finder's Window and use the GO Menu.

At the same time hold the ALT key down.

Select the Library that appears in the Menu list and then Navigate to Preferences.

Delete all the items that Start com.apple.iChat and end in .plist

Also delete com.apple.imagent.

Follow that by also deleting

com.apple.imservice.ids.iMessage.plist

com.apple.imessage.plist

com.apple.imessages.bag.plist

In the Home Folder/Library there is also the Messages folder.

Deleting the three Data bases will remove all records of the iMessages you have had.

It also removes the Summaries of any Saved Chat you may have made in the past.

Those are stored in ~/Library/Containers/com.apple.iChat/Data/Library/Messages/Archive

IN this Messages folder there is also an Alias to the Attachments in the ~/Library/Messages/Attachments (where the database items are)

There are more .plist in ~/Library/Containers/com.apple.soagent/Data/Library/Preferences

Start with com.apple.messageshelper.AccountInfoController.plist and works down the few with messagehelper in the name that are actual files and not Aliases.

Doing all of this is likely to cause Messages to be reset as far as Preferences, some Menu choices that can be made and other peripheral settings, along with the History to the Messages you may have had.

It is unlikely to sort out the issue with the File/Picture Transfers

8:48 pm Wednesday; February 14, 2018

Hi,

IF the app is not doing Picture or File sending properly both for Receiving and Sending then it can be down to several things.

Firstly this Agent needs to run

/System/Library/PrivateFrameworks/IMTransferServices.framework/IMTransferAgent.a pp/Contents/MacOS/IMTransferAgent

Secondly that needs to be allowed to contact this server

"Allow outgoing TCP connections to port 443 (https) of gcs-eu-00002.content-storage-upload.googleapis.com" (from Little Snitch)

Now this does not look like an Apple Server and if you are using a Firewall app similar to Little Snitch then it may be blocked there.

I am also not entirely sure that the Server stays the same.

If you have Activity Monitor open when attempting a Transfer then the IMTransferAgent should appear briefly in the list of activate apps and processes.

It quits as soon as the Transfer is made.

Some people seem to be saying the IMTransferAgent.app is missing from the above location.

The only way to get that back is to Reinstall the OS.

9:12 pm Wednesday; February 14, 2018