I am running Quicken Premier 2017 (r15.1) and I am about to install Quicken Premier 2018 . (Windows 10 Fall Creators Update) Can they run alongside each other. They will have separate QDF files. I see this question was asked about previous versions. I want to know specifically about the NEW 2018 vs 2017.
I need to do this because I have two securities that show a conflict between the
"Shares" on the holdings page and the
Number of Shares on the Sell - Shares Sold page when you select "
Sell all shares in this account". (See below.) (By the way, the Daily Gain/Loss calculation on the Investment Tab uses the Number of Shares on the
Sell-Shares Sold page.

I have tried various combinations of file copy & file validation to no avail. When I run a security activity report every buy, sell, reinvest div ... is there. The "number of shares" available to trade are short by the quantity of the last trade. I deleted that trade but no joy. (This is true for the second security as well.)
I think the only way to solve this is by reentering all of the security transactions. I have dividends going back to 1977.
It is going to take time; first I have to delete each transaction and then reenter them. Perhaps in the future there will be a way to export all of the transactions for a specific security and then with a click of a button delete all of the transactions and then click another button to import the exported file. Long over due, no?
I am afraid that during the conversion of the file from 2017 to 2018 something my not carry forward to the new QDF file. I want to be able to fire up the 2017 version to help reconcile any problems I may encounter. I won't be updating the 2017 file; I just want it for reference: security transactions, gain/loss reports, transfers, etc..
What do you think?
Fred J.