Fatal error Upgrade from 2.9 to 3.0.3 [SOLVED]

I just upgraded to the latest version and on my first run I get a fatal error.

Compiling scripts:

  • script: “mainscript.c”…
    fatal error #1061: Can’t open input file ‘Z:\DOCUMENTS…\Compile\bin\mainscript.c’.
    A fatal error has occurred:
    Compilation Failed for Script "Z:\DOCUMENTS…\Compile\bin\mainscript.c

Any ideas where to start on this one?

Writing to a mapped drive caused the problem. Solved by Support.
Went to Advanced build options and set a temporary folder on C:\ drive. Problem solved.