To solve this use Win + R, then type in appdata and hit enter, then open the Local Folder, and delete the folder FFXIV_TexTools2 in there, and start TexTools again. Before we begin, it's important to note that you're going to need an application called FFXIV Textools.
Mod Release Channels: #textools_releases. The official TexTools website and download links. This is one of the more heavy-duty FFXIV mods on the list.
