@StarshipKnight That's a generic error message when the compilation (and the follow-up installation) fails. You'll find the detailed error message in the ~/RetroPie-Setup/logs folder, in the most recent log file.

Also noticed that RetroPie setup basic_install doesn't pass on Ubuntu 20.10 x64. I suspect this might be related to recent RetroPie/Retroarch updates more so than testing it on 20.10 though. But just wanted to drop it here as I have the logs in front of me now (will test on 20.04 soon). Edit #1: tested on a clean 20.04.1 and 20.10 VMs. Looks like this only happens on 20.10. GCC on 20.04 is 9.3.0 and on 20.10 it is 10.2.0. Edit #2: Looks like this is caused by Ubuntu 20.10 upgrading to GCC 10.x. Created new thread with a workaround here. ... Getting sources for 'lr-mupen64plus' : N64 emu - Mupen64Plus + GLideN64 for libretro = = = = = = = = = = = = = = = = = = = = = git clone --recursive --depth 1 --branch master "https://github.com/libretro/mupen64plus-libretro.git" "/home/pi/RetroPie-Setup/tmp/build/lr-mupen64plus" .... /home/pi/RetroPie-Setup/tmp/build/lr-mupen64plus /home/pi = = = = = = = = = = = = = = = = = = = = = Building 'lr-mupen64plus' : N64 emu - Mupen64Plus + GLideN64 for libretro ... ... g++ -march=native -O2 -fvisibility-inlines-hidden -std=c++11 -O2 -DNDEBUG -fsigned-char -ffast-math -fno-strict-aliasing -fomit-frame-pointer -fvisibility=hidden -DGIT_VERSION=\"" ab8 134a"\" -DOS_LINUX -DARCH_MIN_SSE2 -msse -msse2 -D__LIBRETRO__ -DUSE_FILE32API -DM64P_PLUGIN_API -DM64P_CORE_PROTOTYPES -D_ENDUSER_RELEASE -DSINC_LOWER_QUALITY -DTXFILTER_LIB -D__VEC4_O PT -DMUPENPLUSAPI -I./custom -I./custom/mupen64plus-core -I./custom/android/include -I./custom/GLideN64 -I./GLideN64/src -I./GLideN64/src/osal -I./mupen64plus-core/src -I./mupen64plus-c ore/src/api -I./custom/mupen64plus-core/plugin/audio_libretro -I./libretro-common/include -I./libretro -I./GLideN64/src/inc -I./xxHash -I./libretro-deps/libpng -fPIC -DCORE -DHAVE_OPE NGL -DDYNAREC -c GLideN64/src/ShaderUtils.cpp -o GLideN64/src/ShaderUtils.o In file included from GLideN64/src/ShaderUtils.cpp:3: GLideN64/src/ShaderUtils.h:10:52: error: ‘string’ in namespace ‘std’ does not name a type 10 | void logErrorShader(GLenum _shaderType, const std::string & _strShader); | ^~~~~~ GLideN64/src/ShaderUtils.h:6:1: note: ‘std::string’ is defined in header ‘<string>’; did you forget to ‘#include <string>’? 5 | #include "Combiner.h" +++ |+#include <string> 6 | GLideN64/src/ShaderUtils.h:11:93: error: ‘std::string’ has not been declared 11 | int compileCombiner(const gDPCombine & _combine, Combiner & _color, Combiner & _alpha, std::string & _strShader); | ^~~~~~ make: *** [Makefile:433: GLideN64/src/ShaderUtils.o] Error 1 make: *** Waiting for unfinished jobs.... Removing additional swap /home/pi Could not successfully build lr-mupen64plus - N64 emu - Mupen64Plus + GLideN64 for libretro (/home/pi/RetroPie-Setup/tmp/build/lr-mupen64plus/mupen64plus_libretro.so not found). Errors: Could not successfully build lr-mupen64plus - N64 emu - Mupen64Plus + GLideN64 for libretro (/home/pi/RetroPie-Setup/tmp/build/lr-mupen64plus/mupen64plus_libretro.so not found). No module 'splashscreen' found for platform x86