Best guess is to delete everything and redownload.
I had a few crashes and errors a while back when the stages was updating, because I didn't really understand how the DLC was already incorporated by the poster, and when the adult version and betas started coming out, I sort of dumped things in the wrong spot and messed everything up.
Saves can be found in the Game folder (I think, don't quote me, it's been a while, and I think that's where Ren'py puts it), you can take that out, delete everything else, then put it into the new download's game folder; Itch.io has the voice files out for free, so you can toss that (back) in there (game folder) as well.
If you just download "Our Life: Beta Build 0.98 (Cove Wedding DLC Intro!)" that's all you need, and if you want the 18+ version, download "18+ Patreon Bonus" to a separate spot, as these are two different games. This should give you the latest of everything, I believe. (I think "OurLife-v1.4.0" is just the official release of everything without the WIP beta content, so if I'm wrong and DLC is missing, or you don't want the beta, download/play that one instead, I guess...)
Everything else is just pieces of DLC in case you've maybe downloaded it somewhere else, or purchased other content and just want one particular DLC and stuff, I believe.
Disclaimer, don't quote me on anything and take this with a grain of salt, I don't really know what could be your problem, and everything has worked on my end since I've played it, so you can give it a try and see if it helps. Good luck!
