Thanks for the details, it’s a very weird issue and we haven’t faced it before. Could you please try to reinstall .NET Framework, you can download the latest release at https://www.microsoft.com/net/download/dotnet-framework-runtime
If you still have this issue, please save the NLog.config file into the application folder C:\Program Files (x86)\SQLBackupAndFTP, restart “SQLBackupAndFTP (SQL Server backup)” Windows service, run the application and reproduce the issue. After the issue is reproduced please send us all log files from C:\Log\SBF folder.
To download Nlog.config file please follow this link https://www.dropbox.com/s/qsxhu9gz1k0rqf5/NLog.config?dl=01
To make your logs private please send them to email@example.com
Also, please check your Windows Event Log (Application and System) are there any error messages related to SQLBackupAndFTP or .NET Framework?
Could you please clarify what OS do you use?
Sorry for the inconvenience.