Taken from the RM site
How to Manage Disk Space on RM Connect 2.3/2.4
Drive C:
To release space on the C: drive:
Search for all *.tmp, *.dmp, *.chk, and *.$$$ files, and delete them.
Search for backup.log and delete this file if it is very large.
Empty the C:\Temp and C:\Winnt\Temp folders if they exist
Delete the folder C:\Support (This contains the Service Pack and SRP files, these can be downloaded or reapplied from CD - please refer to DWN6361 in the Other Useful Articles section below).
Delete Temporary Internet Files for all users within C:\WinNT\Profiles, e.g. C:\WinNT\Profiles\Default User\Temporary Internet Files\, C:\WinNT\Profiles\Administrator\Temporary Internet Files\
Uninstall programs from Control Panel / Add/Remove Programs that are not required on the Server, e.g. MS Office, etc.
Empty the Recycle Bin.
Search for Pagefile.sys. If it is particularly large, consider moving it to the D: drive (please refer to TEC105319 in the Other Useful Articles section below).
Check the size of the Spool folder. This can be moved to D:, if auditing is not a required function.
Run a full chkdsk on the C: drive.
Drive D:
To release space on the D: drive:
Search for all *.tmp, *.dmp, *.chk, and *.$$$ files, and delete them (do NOT delete any .log files).
Empty the Recycle Bin.
If you have users account on the system which are no longer required (e.g. the user/group of users have left) then delete these users from within RM User Manager to free up additional space. (You may wish to backup the Users area for historical data before deleting the accounts).
Check how much space the users directories are using (right click on the folder, and select Properties). If a large proportion of the used space is in the users' area, you may wish to consider reducing the allowed space, or moving some users to another drive (see TEC12393 below). Some users may be using excessive amounts of space to store files such as *.mp3, *.avi, it is always worth checking for these on a regular basis.