It’s my understanding that the script that is available to convert a secondary data set to a primary data set does not work with 2019. Probably due to 2019 using java 11.0.1 instead of 1.8.0_162.
Until support come up with a new script you could uninstall 2019, install 2017 run the script on that and then update to 2019. I have not tested this myself, but I think it should work.
Make sure you make a EXPORT BACKUP of your 2019 data set first in case something goes wrong.
Just had a conversation with Sean the Moneydance software developer and he thinks the script should still work. So as we were talking I did a backup of my secondary data set then restored from backup so I could run the script on it.
The script converted the secondary to a master data set. The grayed out don't sync from my restored backup was active again and I could change syncing method.
Can you try again this time follow the above on you 2019 secondary data set. Post any error messages you get.
Suggest you restore from 2019 backup before you try again.
The script you are running has the wrong extension, it should be “py” not “css”.
Download again and make sure the extension is not being changed.
To make sure, use OPEN SCRIPT when EDIT SCRIPT and you should see the attached.
CLOSE EDIT before RUN.