I have been a Quicken user for 20+ years. I have a subscription and today updated to the latest Quicken Classic Version. I have been reconcilingmy simple checking account for years and always had no problems. Today for some reason the opening balance from the prior reconcile was incorrect. To make a long story short I eventually used the online balance to reconcile and found I had to adjust my balance by a considerable amount. Not sure what happened. I checked to see if there were unreconciled transactions anywhere and there weren't.
I also went back to the prior back up file and the same thing happened so it wasn't an update issue.