To delete settings (it can be useful in case of troubles like white screen with LotAtc…):

With LotAtc 1.2.3

Delete with regedit.exe the directory Computer\HKEY_CURRENT_USER\Software\DArtSite\LotAtc 4 DCS Client

With LotAtc 2.x

Delete the file C:/Users/you/AppData/Roaming/DArtSite/LotAtc Client.ini