Does the original printer setting you removed reappear when you restart? That would indicate that the settings are not being saved. There are many reasons why that can happen. The two most common these days is having the profile on some sort of network drive/NAS/Cloud synced location and having an antivirus program scanning in the profile folder and preventing the necessary writes to update the preferences.

A clue to either of this being the issue is the existence of files in the profile folder with numbers appended to the names. look for files names prefsXX.js where the XX is a number usually between 1 and 99

To open the profile folder go to the troubleshooting information on the help menu and click the open button beside the profile folder entry.

The profile is stored locally. There are no odd profile names either

Try this: Help/Troubleshooting Info, Printing (bottom of tab), Clear saved print settings, restart TB. Is the system default printer detected in the Print dialog?

That's how I get it to come back, but it disappears upon next start up. The only printer that shows up in the print dialog is Save as PDF

I had the same problem and fixed it by click print and scroll down to the bottom of that print window select "Print using the system dialog…" delete all the printers listed that you don't have any more or can't print to.

After that, verify I can print to the printer I want from the "Print using the system dialog…" Now, try again to print normally. The old printers should be cleared and the one you can print to will work.

This fixed my problem