I installed from the downloaded file SynfigStudio-1.2.2-18.09.14-win64-286f1. During installation in the very first step after license agreement the check box for Synfig Studio (64 bit)- required is inactive and it cannot be checked. So, after installation the software cannot be used and every time it stops giving an error message. Advise
Not much experience with the windows version of Synfig, but maybe try to uninstall Version 1.2.2 and try Version 1.3.11 instead.
There is also a portable Version of Synfig perhaps use that one.
Or simply scroll down the license agreement, sometimes (meaning other software) the checkbox only becomes active when it seemed like you read it through, aka reached the end of the page.