Yep, happened to me.
***Caveat: Do these steps at your own peril - not responsible if anything goes wrong.***
It can be the battery inside the computer case may be loose and the computer isn't booting the correct drive. If you are comfortable replacing your own computer battery here is some information on how to get to the computer.
Video of how to take it out of the computer is here (Thanks to brenna98 for the videos and being an all around awesome human being).
Also - Open a support ticket with American Pinball as well.
Also you can try this:
Check Boot order in the BIOS
With a USB keyboard plugged into the computer (or usb extension inside the coin door), power on the game while you press and hold the ‘delete key'. This should take you to the BIOS screen, if it doesn’t, try again.
At this point, arrow key over to the “Boot” tab screen. See which order of boot 1,2,3 is listed. “Boot Manager” should be boot 1. If not, arrow down to the boot 1 spot, push enter, then arrow down to Boot Manager and push enter to select. Now arrow right to the save/exit tab screen; push enter to save/exit to make the computer reboot.
If you did not see “Boot Manager” in the boot tab screen, there is an operating install process but I am not going to post that here and best to check with American Pinball for the latest and greatest (unless Dave says it is okay for me to post it with the American Pinball links here).
Good luck, it is annoying and scary but it can be corrected