Windows cmd usually works with "\" and with "/" for pahts you can:
cd C:\AM\emu\retroarch
or
cd C:/AM/emu/retroarch
But you are right I made a search and replace and some "/" became "\" I´ll paste a complete log code with your paths at the end.
But this is not important , the "important" part of the code is this:
--verbose >> fba_log.txt 2>&1
This will create a fba_log.txt with your error , so try to create it.
P.D My working code is this:
# Generated by Attract-Mode v2.2.1-43
#
executable cmd
args /c cd "C:\AM\emu\retroarch" & start /wait retroarch -L cores\fbalpha_libretro.dll "[rompath][name].zip"
rompath C:\AM\emu\retroarch\system\roms\
So , try adding "--verbose >> fba_log.txt 2>&1"
# Generated by Attract-Mode v2.2.1-43
#
executable cmd
args /c cd "C:\AM\emu\retroarch" & start /wait retroarch --verbose >> fba_log.txt 2>&1 -L cores\fbalpha_libretro.dll "[rompath][name].zip"
rompath C:\AM\emu\retroarch\system\roms\
P.D.2 Forget "absolute paths" if you cant launch the core , first try complete paths and generate a log , then you can create relative paths and more sfuff.
executable ..\..\emulators\RetroArch_1.7.3_x64\retroarch.exe
args -L ..\..\emulators\RetroArch_1.7.3_x64\cores\genesis_plus_gx_libretro.dll "[romfilename]"
rompath ..\..\roms\mastersystem
P.D.3 Can you launch any rom without command line?I mean try 1942 , for example , because maybe you have a non working set.