Updated to firmware 1.25 arduino wont' compile

Anyone knows what this means?

Arduino: 1.8.8 (Windows 7), Board: “Arduino/Genuino Mega or Mega 2560, ATmega2560 (Mega 2560)”

C:\Users\TYPECA~1\AppData\Local\Temp\ccsxc8Qh.ltrans0.ltrans.o: In function `main’:

:(.text.startup+0x1b6): undefined reference to `setup’

:(.text.startup+0x1ba): undefined reference to `loop’

collect2.exe: error: ld returned 1 exit status

exit status 1
Error compiling for board Arduino/Genuino Mega or Mega 2560.

This report would have more information with
“Show verbose output during compilation”
option enabled in File -> Preferences.

No idea what that error means.
But we recently had a Forum member having a problem because his user-name/user-folder had an @ in the name. He created a new user with ‘normal’ letters and it worked. Do you have any symbols in the name of your user folder that are symbols, not letters?