My website is hosted in Windows server 2008 R2. We have a software for which updates are downloaded using winsock from our websites. It works properly for all customers(more than 20000 for last few years). In some Computer of my customers I found that the it downloads old file from a website instead of new file. For example instead of downloading update.txt, it downloads file update.txt.old with name update.txt .Actually update.txt.old is the old file we keep in server.
I have checked browsing the file using chrome and proper file is downloaded. I tried using netsh winsock reset command , resetting Internet explorer, clearing cache, temporary files etc and problem didn't solve.
So is there anyone who know about this strange error , how can I troubleshoot?