I did not get a solution before and continue to have daily issues with Quicken for Windows creating duplicate securities during a download, and then the original security with the buys and dividends "disappears". If I click on the name it is there but does not populate the transaction list to make changes.
I cannot delete the new security so they other sit there. One with many transactions the other with only one
I have tried to "merge" the two by making all of the information identical but Q says "You already have a security with that name"