Dec 13, 2016 - Simply scroll down to 'Legacy Peripheral Libraries' 'PIC18F' and pick the installer for your OS. Sorry, my bad, should have said MPLABX 3.45. With a very bloated computer by installing the files to support one's old designs. Fixed MAC address that you have a licence for, install the licence(s), and then.
I had copied a project that was builder in older MPLAB X IDE 3.x which I was opening in freshly installed MPLAB X IDE 4.05 but it was complaining about not find plib.h library which was referenced in the code. I did a couple of days of digging into and now found the problem using this The installer “PIC32 Legacy Peripheral Libraries – Windows” from here asks for the installation directory during installation, even if you have only one XC32 version installed. In my case it proposes: C: Program Files (x86) Microchip xc32 v1.40 which is “wrong”, because I only have v1.43 installed. It proposed the wrong directory, and if you simply accept, it will use that wrong path. As a consequence you cannot use the peripheral library (without changing project paths) Install it again into your “current” compiler directory. I could imagine its a bug, but they won’t fix it for the legacy PLIB. Which was exactly the problem.
The problem was older version of MPLAB X IDE uses legacy drivers (plib) while they have been abandoned in the newer version. Verse legacy drivers are not shipped with the latest version of MPLAX X 4.05. To sum up the problem for a newbie, to make older code work in the latest MPLAB X, you have to do the following. Install MPLAB X V4.05 (latest by today). Intall X32 C-Compiler (you have to download this sperate). Install “PIC32 Peripheral LIbrary” (You have to it first).
When you install PIC32 Peripheral Library, it will try to install itself in XC32/1.40 folder but you have to change that. This is the trick that you have to apply. Simply supply it the path to XC32 folder, which must already exist and continue with the installation. That should solve your problem of “not finding plib.h” which is the peripheral library for legacy (older) MPLAB. In Microchip MPLAB IDE 8.92, “Microchip PIC32 C-Compiler toolsuite” were not showing. If that is the case, you just have to click t he checkbox “Show all installed toolsuits”. Here is t he complete list of compilers This is what you see if you dont check the checkbox There is a related topic on where the suggestion is that you need to register the DLL but here you don t have to do that.
Update The reason C32 compiler is now showing up could be because the right microcontroller is not selected (it does not support C32). There is a bug in MPLAB, if you select MX32 bit microcontroller in the first project, it selects the default 8-bit micrcontroller instead, hence 32 bit options are not showing by default.