Since the last update 12.7.2 my itunes will not burn from downloads b will burn from a prerecorutded CD

There would appear to be a general issue burning from iTunes 12.7.2.x for Windows.

A workaround is to uninstall iTunes then download and install one of the following as appropriate:

• iTunes 12.7.1.14 for Windows (32-bit) - iTunesSetup.exe (2017-10-30)
• iTunes 12.7.1.14 for Windows (64-bit) - iTunes64Setup.exe (2017-10-30)

Are you saying the issue only affect CDs you make with iTunes store purchases and, for example, that a CD that only contains tracks previously ripped locally will burn without error?

tt2

iTunes 12.7.3.46 for Windows has been released which appears to burn CDs normally.

It can be downloaded from https://www.apple.com/itunes/download/.

tt2