Twice in the last several months I have reconciled my checking account but could not make it balance. I discovered that the reason was that a reconciled transaction from 10 months ago had disappeared and another transaction was put it in its place. The new replacement transaction was a duplicate of another transaction already recorded in that month. The transactions were both auto entered monthly health insurance payments. I know where to look for this problem now, but it is very irritating.
I am using the Windows version.