The MPLAB® X Installer places a dedicated copy of the Java runtime environment inside the MPLAB X IDE directory structure. This practice enables us to keep MPLAB X IDE stable by pairing it with the same version of Java with which it was tested, even while the main copy of Java on your machine gets upgraded periodically. The version installed with MPLAB X is "isolated" and does not interact with any other copies of Java or programs written in Java that you may have on your machine.
Recently, we have been informed that some recent versions of the Java runtime environment don't work well with older processors, such as the AMD Athlon XP, where the instalers and IDE may crash. If you are still working with very old hardware, you might need to replace the dedicated Java Runtime Environment installed with MPLAB X IDE with an older version to get MPLAB X IDE to work at all.
This procedure is NOT recommended, but is presented as an option of last resort if you are determined to run MPLAB X IDE on very old hardware. Using older versions of Java can create security vulnerabilities on your machine and could make MPLAB X IDE unstable in other ways since the current versions of MPLAB X IDE were not tested with older versions of Java.
Downgrading Java of installed MPLAB X IDE
1. Obtain a copy of an older version of Java (such as JRE1.7.0_25):
- Download from Oracle's Java archive
- Use a copy of the Java Runtime Environment already installed on your system
- Use a copy from an older installation of MPLAB X IDE
2. Then, replace the JRE located at C:\Program Files (x86)\MICROCHIP\MPLABX\sys\java\jre1.7.0_67 with the files from the older version.
Workaround for Crashing Installer
1. If possible, install MPLAB X IDE on a newer machine, then copy all the files from C:\Program Files (x86)\MICROCHIP\MPLABX to the older machine.
2. Follow steps above to downgrade Java.