var source = @"C:\Users\lucian.bargaoanu\AppData\Local\Packages\Microsoft.WindowsFeedbackHub_8wekyb3d8bbwe\LocalState\{3e013fe7-2abf-493f-9d14-8c96bd350762}.txt";
var afterBackSlashIndex = source.LastIndexOf('\\') + 1;
var s = new StringBuilder(source)
			.Remove(afterBackSlashIndex, source.Length - afterBackSlashIndex)
			.Replace('\\', '/');
s.ToString().Dump();