Sorry, I don't know what "optifine" is.
Adobe Reader can only open PDF files.
As Pat says, Adobe Reader only opens PDF files. I think you may have better luck contacting Optifine to find out why it's not working as you expect: https://optifine.net/home.
The issue isn't that Optifine fails to function properly, it's that Adobe forced itself to be the default application for running .jar files.
Adobe can only SUCCESSFULLY open .pdf files, but for some reason also thinks it can run .jar files.
There is no need for Adobe to open them, as .jar files should be able to run themselves; they are a self-executing program.
I've had this problem since I got my computer, and since I work with .jars a LOT, it's become very frustrating, having to uninstall and reinstall Adobe before and after I open every .jar.
To solve this issue, there needs to be a way for a user to disable Adobe from being the default application without needing to uninstall it, or at least fix Adobe from thinking it can run .jar files.
So no, contacting Optifine would be of no use.
Adobe needs to fix this error.
P.S: Optifine is a user-made modification to Minecraft, which allows for better graphics optimizations, intended for low-end PCs. For some people, it's required to run the game, so if someone doesn't know how to get around this issue, then they will be unable to play Minecraft with their current computer.
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download and install jarfix. it will allow you to install it as long as you have java installed