Xmedia Recode suddenly stopped converting videos and would immediately abort the process with the error message "An error occurred when converting. Total processing time: 00:01"

As part of troubleshooting this, I changed the "Profile" (In the Format tab, next to "Queue") from my usual "custom" to another random one and tried to convert using those settings. XMR converted the file! I then set it back to my custom format and XMR converted my files as usual. I did have to redo some of my settings.

Putting this info out there in the hope that it helps others...