This question already has an answer here:
I know this is not a reasonable request but is it possible to reset master DB to the status it was just installed without backup?
I deployed a DB project which I didn't know it will mess with master DB so I didn't backup it in advance plus the deployment script has some defects so the process failed and left tons of rubbishes in master DB.
I did a bit search but most of the instruction requires a backup whereas I can't be sure for those don't request backup can work master DB around or not.
Is there any way else except reinstalled the instance all over?