I wrote a tool to backup and sync my folders. (Tool written in Visual Studio 2022 with .NET Framework 4.8) To copy the files I use System.IO.File.Copy(sourcePath, targetPath) To compare the files I use System.IO.FileInfo.LastWriteTimeUtc I create my backup on a USB stick. After the automatic summer time changeover (+1 hour), all time stamps in Windows file system have changed (added 1 hour to LastWriteTime and LastWriteTimeUtc). Now, my tool wants to update all files. This is currently not a problem, but it will be a problem with the clock reset to winter time in October. Then files in the target are more up-to-date than in the source.
Why is the date stamp changing? Is that normal? Do I have to check the time zone when comparing? But I thought the UTC timestamp is there to not do that...
Here a picture from one FileInfo (This phenomenon occurs with several thousand files): enter image description here
