To fix issues with Windows 10 ignoring external manifest files (which control .exe window sizing, etc) with regedit, verify that the

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\PreferExternalManifest

AND

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\SideBySide\PreferExternalManifest

DWORD is set to true.

If these DWORD entries don’t exist, then create them and assign them a true value.

Once complete, restart windows.