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Go in MT Securty Settings > MassCore tab.
Click on Uninstall MassCore, and press OK. Your computer will reboot.
As you will install a MassCore Engine version using the same authorization code, you will not need to re-authorize the MassCore RTX License.
You are now ready to update to Spring Creator 1909Windows 10 2004 / 2009.
UPDATE WINDOWS TO 2004/2009
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