I’m sure it’s happened in other versions of Windows too. Everything will be fine, then out of the blue you start getting errors like this:
0 [main] us 0 init_cheap: VirtualAlloc pointer is null, Win32 error 487
AllocationBase 0x0, BaseAddress 0x71110000, RegionSize 0x3B0000, State 0x10000
d:\mingw\bin\sh.exe: *** Couldn’t reserve space for cygwin’s heap, Win32 error 0
make: *** [all] Error 1
Well MSYS like Cygwin uses persistent shared memory locations, and if they become corrupt, it’s game over.
So yeah, reboot.