Those files are created by notifications. If the "Write to file" option is set to "Yes" in a Notification Method, the context information of the Notification Method is written to a file. You can check the setting as per below.
- Log into Service Desk using Administrator account.
- Go to 'Notifications' > 'Notification Methods' and check each Notification Method from the list.
Also, if a custom method fails to sent out the notification, the files might be created under TEMP folder. Check stdlog if the following or a similar error was written.
12/07 15:21:17.08 SDMSV bpnotify_nxd 1952 ERROR bpnotify.c 267 couldn't start process mapi_mail -m C:\WINNT\TEMP\33: GetLastError= 
If the files were created by the Notification Method or Notification failure, you can delete them without recycling Service Desk Manager.