I am using Quicken Classis Premier version R62.16 on a Windows 10 PC and have never had a problem in the past 10 years or so. Today, I downloaded some transactions from my bank and everything was fine in my checking, savings and credit card accounts. I accepted a few transactions and backed up the file (I do it every day with the date appended). I left the PC for about 5 minutes and all of my checking account register dates had changed. All of my 2025 transactions now are dated 2014 as well as earlier transactions. I did not check the other accounts and pulled in today’s backup with the same problem. I then pulled in yesterday’s database and pulled in the downloaded QFX files and accepted them and now everything is fine. I backed up the file and pulled in back in overwriting my current file and it is still OK. I have no idea what caused the glitch, but I am OK for now.