The .properties Directory Editor for Portable TLauncher made by moiSentineL here.
This application written in Python will solve the problem of TLauncher not recognizing the current directory as the main .minecraft folder.
This application searches for the tlauncher-2.0.properties file inside the .tlauncher directory and edits the minecraft.gamedir value to the .minecraft folder existing in the USB Drive.
Download the zip file from here
Extract it onto the root folder of the Portable Minecraft (i.e. the folder which contains the tlauncher.jar.
Open the folder and run tl-directoryeditor.exe. You MUST run the file from correct directory,
Correct Directory Example:
📦 Root Folder
┣ 📂tl-directoryeditor
┣ ┗ 📜tl-directoryeditor.exe <-------- You run this.
┣ 📂JavaPortableLauncher
┣ ┗ 📂Data
┣ ┗ 📂AppData
┣ ┣ 📂.minecraft
┣ ┗ 📂.tlauncher
┣ ┗ 📜tlauncher-2.0.properties <-------- The file which is going to be edited.
┣ 📂CommonFiles
┗ 📜tlauncher.jar <-------- Make sure this file exists in the root directory.