The location of the logger files depends on the version if windows you are running.
For Windows XP the default location is:
C:\Program Files\TempIT V4\Logger Files.
For Windows Vista, Windows 7, Windows 8 and Windows 10 (UAC on) the default
location with be:
C:\USERS\*******\AppData\Local\VirtualStore\Program
Files\TempIT V4\Logger Files
******* replace with your username.
Each logger has a database file with the extension .sdb. The serial number will make up part of the file name The database contains all graphs downloaded from the logger. You should rename your files if you are placing them in the same directory as existing database files.
Also make sure you are running the latest version of TempIT