Empirical workaround to restore sharp window corners on build 26200.3584

[ejkcor-hash]

I’d like to share an empirical workaround that restored sharp (non-rounded) window corners on Windows 11 Insider build 26200.3584, using ExplorerPatcher 26100.4946.69.5.
Context:
• Build: Windows 11 Insider 26200.3584
• ExplorerPatcher: 26100.4946.69.5
• StartAllBack: 3.9.16 (installed and then uninstalled)
Steps (empirical, not guaranteed):

1. Installed ExplorerPatcher
2. Enabled "Disable rounded corners for application windows" under Other
3. Installed StartAllBack and enabled all Windows 10-style options
4. Uninstalled StartAllBack without rebooting
5. Restarted Explorer manually
6. Result: sharp corners restored
   Important conditions:
   • StartAllBack must be removed for corners to activate
   • Windows Update must be fully disabled
   • ExplorerPatcher updates must be disabled
   Remaining issue: Modern UI surfaces like the Search flyout and Copy/Move dialogs still have rounded corners. Possibly due to UWP/XAML rendering isolation.
   This is not a stable or recommended method, but it may help others experimenting with UI consistency. Thanks for your work on ExplorerPatcher.

[pyrates999]

I don't understand why anyone wants square corners for windows in windows. Do none of you remember what windows 7 looked like? It was glorious!