stop saving archive files

By "archive" files, I'm assuming you are talking about the 5MB log files that are probably increasing is number on your server.

If so, these are Transaction Log files and are an important part of Exchange's ability to recover from disaster. Theycannot be manually deleted without possibly suffering grave consequences.

There are two ways to prevent these log files from accumulating:
1. Implement Circular logging. This creates up to a finite number of log files (7, if I remember correctly), and then reuses the same log files as needed. This setting is not recommended if you don't back up your Exchange installation on a regular basis.
2. Back up Exchange on a regular basis. When using an Exchange-aware backup program, all log files are automatically deleted once they are backed up using either a Full or Differential backup.

Another option if hard drive space is becoming tight is to install a larger hard drive and use the Exchange Performance Optimizer to move your Information Store, and/or transaction log files to the larger drive.

Hope this helps.

Thanks to Mr.tim but what do I mean with "archive files" is the files that are saved in two folders ("In" folder and "Out" folder) in (imcdata) under exchange server folder.