Recently, I've upgraded MPLab from v8.40 to the MPLab X v5.4. (I had first used the MPLab X v5.30, but due to a requeriment from my profesor I had to downgraded to the MPLab v8.x)
Now, I can't create a new project, because in step two, instead of "Selecting Device", it shows "Target Location" (as depicted in the first picture). But, it does't let you "pick" any folder nor file. Also, at starting the program, it show a notifaction under the label "Unexpected Error". When clicked it says "Could Not Find Pack Repo Provider". In the details of the error, it says "java.lang.UnsupportedOperationException".
With the both versions I had previously installed there was no problem with the project creation, nor with the project wizard. But as of this time, MPLab marks an error with Java (I have Java Developer Kit installed as well as Java 1.8.0). After some digging I read that MPLab uses it's own Java.
I have uninstalled and installed MPLab X versions 5.30 (again), 5.35 and 5.40 several times (probably 10), making the "complete" uninstalling, but when I reinstall it just shows the same problem. I'm out of ideas to solve the problem as I have ininstalled Java from my computer already (with the Developer Kit) to see if that could solve it, but it was futile, so i installed them back.
I had the same problem (I know this post is old but in case...).
I just have to uninstall MPLABX, delete "C:/users/username/.mchp_packs" folder, install MPLABX.
I love this IDE (...sarcasm...)