This issue pertains specifically to Minecraft, but it is affecting all Java programs that run on my computer.
It would seem that something is forcibly setting a _JAVA_OPTIONS environment variable. When I run my server, I have specified to allocate 4 GB of RAM to it with
-Xms4G -Xmx4G
in the startup batch file. However, when the server runs, It prints "Picked up _JAVA_OPTIONS: -Xms2048M -Xmx2048M" to the console, only allocating 2 GB. I have checked my system settings and there is no _JAVA_OPTIONS environment variable in the list. I do not want to add one, since that will also try to allocate 4 GB to Minecraft itself, which is unnecessary and uses too much RAM.
What could be causing this variable to be set? (Windows 8.1 64-bit, Java 7)