When _JAVA_OPTIONS is set to anything in Enviroment Variables, it makes the launcher says the launcher is corrupted and that should reinstall:
Values tried:
Xmx512M
-Xmx512M
test
Removing it fixes it, but you have to open it one time, close it and then open it again
Update 16/05/2016:
Another user with same error(Windows 10 x64), the default contents where "-Xmx1g - Xms1g". User said it came back when reinstalling Java 8 Update 91(Browser installer). Fix was to delete the variable and download the Windows Offline installer
Is this still a concern in the current Minecraft Launcher version 2.0.805 / 2.0.806? If so, please update the affected versions in order to best aid Mojang ensuring bugs are still valid in the latest releases/pre-releases. If this has been done, we can reopen the issue.
Keep in mind that the "Resolved"-Status on this ticket just means "Answered", and that we are waiting for further information on whether this issue still exists or not. It will be reopened it as soon as the requested information has been delivered.