I had this same issue and found the solution! You don't have to go through installing the Line 6 Updater software.
The issue is Windows 10 Ransomware Protection, specifically the Controlled Folder Access feature. You will need to allow the Line 6 Pod Go Edit software through that protected folder access and then it will be able to access your "Documents" folder, which is where the software seems to be hard-coded to install the backup files. You can't point it to a different folder, it has to be your user "Documents" folder (which is an oversight on the dev's part, in my opinion). It really should give you an error rather than not showing the modal popup at all...
Here's what you do to fix this:
Close PodGo Edit if you have it open
Open Windows settings, and in the search bar enter a search for "controlled folder access"
It will take you to a page for Ransomware protection with the Controlled Folder Access (likely set to 'on'). Click on the option here called "Allow an app through Controlled folder access"
You'll see a page to allow an app through Controlled folder access. Click on the button that says "Add an allowed app"
Look for Pod Go Edit from your recently blocked apps list, or click "Browse All Apps" and navigate to C:\Program Files (x86)\Line6\Pod Go Edit . Select that file and allow it to the controlled folder access.
Close the settings folder and launch Pod Go Edit again. Now you should be able to create backups! The modal should pop up now and you're good to go through with the update as expected.
After that, just make sure you leave everything alone while it updates the firmware!
