I’m trying to install the latest TD FTE but an older version won’t uninstall because it wants the old msi which I can’t find anymore, so I tried uninstalling it manually, I deleted the folder and tried deleting every instance of touchdesigner in my registry. Now I found the MSI file on the old builds page but it won’t uninstall… 
What to do?
hmmm… might be worth doing a system restore to take you back to how it was before everything went pear-shaped.
but before that, try downloading the latest one and click install. It should update anything that’s still floating 'round in the registry etc.
I think that you only need to uninstall the old one if you are trying to roll back to an earlier build. It’s best to install the experimental ones rather than the stable ones unless you need to be absolutely sure of compatibility with something for work.
Rod.
You can just install newer builds of TouchDesigner without uninstalling the old one. I’d recommend just installing the new build and see if it works.
When you do need to uninstall (going to an older build or removing fro the system), we recommend using the Window Control Panel > Programs and Features panel to uninstall TouchDesigner properly.