I'm trying to create a function to run in my minecraft world and it is not working at all. I've reloaded the world and have it in my minecraft world folder but It won't run it and it tells me its non existent.

Please attach the crash report ([minecraft|http://hopper.minecraft.net/help/guides/finding-minecraft-data-folder/]/crash-reports/crash-<DATE>-client.txt), otherwise we can not diagnose this issue.
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21:48:08 launcher Preparing to launch minecraft client for 1.12
21:48:08 launcher Checking installations.
21:48:08 launcher Minecraft client 1.12 is ready to start.
21:48:08 launcher Starting!
21:48:09 launcher Using default game log configuration client-1.12.xml (outputs XML)
21:48:10 bhz Setting user: TRK500
21:48:12 bib Skipping bad option: lastServer:
21:48:12 bhz LWJGL Version: 2.9.4
21:48:12 cet Reloading ResourceManager: Default
21:48:12 chk Starting up SoundSystem...
21:48:13 chk Initializing LWJGL OpenAL
21:48:13 chk (The LWJGL binding of OpenAL. For more information, see http://www.lwjgl.org)
21:48:13 chk OpenAL initialized.
21:48:13 chk Sound engine started
21:48:17 cdn Created: 1024x512 textures-atlas
21:48:19 com.mojang.text2speech.NarratorWindows Narrator library for x64 successfully loaded
21:48:22 chb Starting integrated minecraft server version 1.12
21:48:22 chb Generating keypair
21:48:22 j Loaded 488 advancements
21:48:22 net.minecraft.server.MinecraftServer Preparing start region for level 0
21:48:23 chb Changing view distance to 12, from 10
21:48:23 pj TRK500[local:E:ff52df6c] logged in with entity id 0 at (856.7514964949268, 107.0, -1456.583702850845)
21:48:23 net.minecraft.server.MinecraftServer TRK500 joined the game
21:48:24 chb Saving and pausing game...
21:48:24 net.minecraft.server.MinecraftServer Saving chunks for level '1.12'/overworld
21:48:24 net.minecraft.server.MinecraftServer Saving chunks for level '1.12'/the_nether
21:48:24 net.minecraft.server.MinecraftServer Saving chunks for level '1.12'/the_end
21:48:24 j Loaded 5 advancements
21:48:35 biz [CHAT] Unknown function 'trk:hi'

Attach the function here.

I also reinstalled the version

Try renaming hi.MCFUNCTION to hi.mcfunction.

Thank you. Very much. Didnt think that would of matter.