You might have to try putting your game somewhere else if it's not already on your C drive. Try placing there possibly.
Depending on where you routed your "option" folder (not sure if this contributes to your issue or not), you might have to route it this way
option=C:\INSERTFOLDERNAMEHERE\app\Package\Sinmai_Data\StreamingAssets .
If that doesn't help, then go into config_common.json and turn off allnet accounting.
Or, depending on the version, it may or may not be an openSSL issue. Command prompt as admin and run setx OPENSSL_ia32cap ~0x20000000
Also if you've downloaded UNi+ files and are looking for maimai FESTiVAL segatools, what you should be looking for is the segatools for UNi+ and not FESTiVAL. You'll need to download FESTiVAL if you're looking for that instead.