I could try on a Windows 10 Pro machine. Would be a different environment though; Win10 Home vs Pro and WinSCP licensed vs unlicensed. I'll report back with results.
Are you able to reproduce the problem anyhow now? Like on a different machine? Would you be able to help us debugging the issue?
Yes, previous installation was from the store. The screenshot is from after the reinstall. The sites were indeed in the INI file. I have since rebooted and the sites returned (thank goodness). However, some sites did not return under the original folders. I'm Ok with this. I consider this a win :)
Were you using Store installation before the reinstall? Can you see the lost sites in the INI file? Can you share the (anonymized) INI file? Is the screenshot from before the reinstallation? Or what does it show?
I decided to re-install WinSCP. After installing, I imported the configuration. Most sites were lost. The 13 sites that were lost were in a folder.
Steps:
1. I exported the configuration. Site Manager-->Tools-->Export/Backup Configuration
2. Re-installed WinSCP from the Windows Store.
3. Imported configuration from Step #1. Site Manager--Tools-->Import/Restore Configuration
Version 5.17.10 (Build 11087) from Windows Store.