Try this for at least a temporary workaround:
- Uninstall Insync
- Reinstall Insync, BUT when the installer asks for admin privilege, deny it.
- Insync will then tell you it can install without admin privilege (but some features will be limited), accept this option.
- Continue to install and run Insync
Insync needs admin privilege to interact with Windows Explorer, to show overlay icons and add entries to context menu etc. Without it, Insync shouldn’t interfere with Windows Explorer.
It’s odd that you’re having these problems even on new Windows machine though. I’m not having such problems on Win 7 or Win 10. Could it be that another program is in conflict with Insync?