After the Intuit Internal Printer or the QuickBooks PDF Converter has been selected as the default Windows printer, you may be unable to unselect it as the default Windows printer.
The cause of this issue is currently under investigation but it is believed that the Windows Unidriver within the Operating System has become corrupt.
To resolve this issue, uninstall all printers from the system and then reinstall them.
In order to remove printer drivers, go to Start, choose Settings, and then choose Printers and Faxes. Right-click on the individual printer drivers and then select Delete. Remove all drivers and then reinstall these drivers.
NOTE: Outside of standard printer drivers that are installed when setting up a new printer, it's possible that various pieces of software may also install their own drivers into this folder. For Example: QuickBooks installs the Intuit Internal Printer driver which creates .PDF files. Other programs may likewise install other non-physical printer drivers as well.
Deleting out these software installed print drivers may require a reinstallation of those other pieces of software to reinstall those drivers.
After deleting the Intuit Internal Printer or QuickBooks PDF Converter driver, you will need to reinstall it.