ppjoy users on Windows have been experiencing a crash on startup; this was a bug in X-Plane 10.10/10.11, induced by particular virtual HID devices that only ppjoy could make. I found the problem and it will be fixed in 10.20.
In the meantime, if you need to use ppjoy and want to work around the problem, set your hat switches to discrete directions, not analog. (X-Plane can't use an analog hatswitch anyway; most people have this because it is a ppjoy default.)
As a side rant to ppjoy users: I was a bit horrified with the process of installing ppjoy. ppjoy is an unsigned driver so I had to turn off driver signing in Windows. ppjoy is also, as far as I can tell, not hosted anywhere official. So I had to install an unsigned driver off of a file locker onto my Windows machine with the safeties off.
To be clear, I do not think that this is the author's fault. He is making freeware, and the only thing that would remedy these problems is money. I do not and cannot expect him to give up not only his time (to code) but also pay to solve the distribution problems of official hosting and buying a signing certificate.
Still, the process of taking off all of the safeties to put random third party binary software on my Windows box was unnerving and not something I would ever do as an end-user.
As far as I know, the ppjoy crash and the PS3 controller crash are the only two known regression bugs* with joystick hardware, and they'll both be fixed in 10.20. (Linux users, needing to edit udev rules to use hardware is not something that we consider to be a bug - see this post.)
When will 10.20 go final? Real soon now. Plugin authors, if you aren't already running on 10.20 betas, you should have been doing that weeks ago.
* Regression bug means: it used to work in 10.05 and stopped working in 10.10 when we rewrote the joystick code.