I recently replaced my Verizon Arris DVR and had issues importing the exported Series Settings (Series Recordings).
I had failed to change the name of the old DVR before exporting the settings on that box so this made things a bit more difficult.
Turns out I WAS able to import the settings into my replacement DVR with a little help from Verizon Support.
The undocumented trick was revealed to me as follows:
1. Go to System in the DVR menu, expand it and then click on System Information. It will blink but otherwise not change the display. IT WILL NOT PROMPT YOU TO ENTER ANYTHING BUT:
2. Enter on your remote the number: 2618 - after you see the Information menu item blink.
3. Be patient and when a dialog box comes up, proceed.
4. Choose the "Unnamed" Series Settings to import.
Note: Say yes to any confirmation popups that may appear.
You should be done. You can check by choosing Manage Series in the left menu and should see your series settings imported into the new box.
Best of luck!
If this doesn't work the first time, try again. It took me two times because I didn't wait long enough for the popup box where you to choose the exported series, to appear.