Set the options as shown by RaceProUK. After that you need to alter the registry...
By the use of a registry key you can change the name of the archive folder to your likings...
eg: the folder
2006-07 is produced by defining
yyyy'-'MM.
The key is:
HKCU\Software\Patchou\Messenger Plus! Live\you@email.com\Preferences\LogsDateDirFormat
Although not yet documented, the format is similar to how the ArchiveFileDateFmt registry key behaved in Plus!3. So you might wanna base your format on the documentation for Plus!3 for now:
http://old.msgplus.net/help_registry.php#datetags
quote:
Date Tags
To add normal text, use single quotes. Example: "dd'/'MM" will produce "18/10".
* d - Day of month as digits with no leading zero for single-digit days.
* dd - Day of month as digits with leading zero for single-digit days.
* ddd - Day of week as a three-letter abbreviation.
* dddd - Day of week as its full name.
* M - Month as digits with no leading zero for single-digit months.
* MM - Month as digits with leading zero for single-digit months.
* MMM - Month as a three-letter abbreviation.
* MMMM - Month as its full name.
* yy - Year as last two digits, but with leading zero for years less than 10.
* yyyy - Year represented by full four digits.
btw, such tags are used in Windows and in many programs btw, so they are kind of 'universal'.
Thus, this indeed also suggests you do not need to specify a date per-say; you can just use a text between single quotes to archive everything into a single subdirectory. Or you can even define the current directory as the archive folder if you define
LogsDateDirFormat as: '.'
Note: there is a very good reason why chats are archived (per month). Chats can become extremely big and the bigger they are the slower everything will get. So be advised that putting everything into the same folder/file is not a wise idea to do actually.
PS: this has been asked for and answered a few times on the forums already. Always search first before you post something 
/ 
