Download, save, and extract the following link:
https://dl.waspbarcode.com/kb/tools/WpfPrinterTest.zip

Run the extracted file, WpfPrinterTest.exe. Click the Test button, and it will return the list of printers loaded in Windows and the page size capabilities of each. If there is an error shown for any of the printers, or if it does not show a page size, that printer will need to have the driver reloaded, or if it is no longer in use it can be removed.

If you find a problem, you can try right-clicking the program, then Run As Administrator. If there's not a problem this time, that indicates a problem with the Windows profile of the original user.

If the first few lines of output are similar to the following, that means there is no default printer set in Windows, which will cause Labeler to crash when clicking the Print tab:

Page range selection  : AllPages
Number of page copies:  : 
Queue:  :  null 
--Enumerating queues-- : ------
---- : ------