I can't open FreeCAD Linkstage3 branch, both Stable and Daily. But FreeCAD main branch working is fine. It may be a AppImage Issue.
Here is the output of terminal when I'm trying to open FreeCAD AppImage
/home/mozammel/Applications/FreeCAD-asm3-Stable-Conda-Py3-Qt5-20210528-glibc2.12-x86_64_76b15da2b46a54d103a358223191e341.AppImage ✔
/tmp/.mount_FreeCAZEhwqf
FreeCAD 0.19, Libs: 2021.528R24301 +3572 (Git)
Sheet Metal workbench loaded
Assembly4 workbench loaded
libGL error: MESA-LOADER: failed to open iris: /tmp/.mount_FreeCAZEhwqf/usr/bin/../lib/libstdc++.so.6: version GLIBCXX_3.4.29' not found (required by /usr/lib/dri/iris_dri.so) (search paths /usr/lib/dri) libGL error: failed to load driver: iris libGL error: MESA-LOADER: failed to open iris: /tmp/.mount_FreeCAZEhwqf/usr/bin/../lib/libstdc++.so.6: versionGLIBCXX_3.4.29' not found (required by /usr/lib/dri/iris_dri.so) (search paths /usr/lib/dri)
libGL error: failed to load driver: iris
libGL error: MESA-LOADER: failed to open swrast: /tmp/.mount_FreeCAZEhwqf/usr/bin/../lib/libstdc++.so.6: version `GLIBCXX_3.4.29' not found (required by /usr/lib/dri/swrast_dri.so) (search paths /usr/lib/dri)
libGL error: failed to load driver: swrast
which: no openscad in (/tmp/.mount_FreeCAZEhwqf/usr/bin:/tmp/.mount_FreeCAZEhwqf/usr/Mod/AddonManager:/tmp/.mount_FreeCAZEhwqf/usr/Mod/Arch:/tmp/.mount_FreeCAZEhwqf/usr/Mod/Draft:/tmp/.mount_FreeCAZEhwqf/usr/Mod/Drawing:/tmp/.mount_FreeCAZEhwqf/usr/Mod/Fem:/tmp/.mount_FreeCAZEhwqf/usr/Mod/Idf:/tmp/.mount_FreeCAZEhwqf/usr/Mod/Image:/tmp/.mount_FreeCAZEhwqf/usr/Mod/Import:/tmp/.mount_FreeCAZEhwqf/usr/Mod/Inspection:/tmp/.mount_FreeCAZEhwqf/usr/Mod/Material:/tmp/.mount_FreeCAZEhwqf/usr/Mod/Measure:/tmp/.mount_FreeCAZEhwqf/usr/Mod/Mesh:/tmp/.mount_FreeCAZEhwqf/usr/Mod/MeshPart:/tmp/.mount_FreeCAZEhwqf/usr/Mod/OpenSCAD:/tmp/.mount_FreeCAZEhwqf/usr/Mod/Part:/tmp/.mount_FreeCAZEhwqf/usr/Mod/PartDesign:/tmp/.mount_FreeCAZEhwqf/usr/Mod/Path:/tmp/.mount_FreeCAZEhwqf/usr/Mod/Points:/tmp/.mount_FreeCAZEhwqf/usr/Mod/Raytracing:/tmp/.mount_FreeCAZEhwqf/usr/Mod/ReverseEngineering:/tmp/.mount_FreeCAZEhwqf/usr/Mod/Robot:/tmp/.mount_FreeCAZEhwqf/usr/Mod/Show:/tmp/.mount_FreeCAZEhwqf/usr/Mod/Sketcher:/tmp/.mount_FreeCAZEhwqf/usr/Mod/Spreadsheet:/tmp/.mount_FreeCAZEhwqf/usr/Mod/Start:/tmp/.mount_FreeCAZEhwqf/usr/Mod/Surface:/tmp/.mount_FreeCAZEhwqf/usr/Mod/TechDraw:/tmp/.mount_FreeCAZEhwqf/usr/Mod/Test:/tmp/.mount_FreeCAZEhwqf/usr/Mod/Tux:/tmp/.mount_FreeCAZEhwqf/usr/Mod/Web:/tmp/.mount_FreeCAZEhwqf/usr/Mod/appimage_updater:/tmp/.mount_FreeCAZEhwqf/usr/Mod/asm3:/home/mozammel/.FreeCAD/Mod/A2plus:/home/mozammel/.FreeCAD/Mod/frame:/home/mozammel/.FreeCAD/Mod/Reinforcement:/home/mozammel/.FreeCAD/Mod/fcgear:/home/mozammel/.FreeCAD/Mod/BIM:/home/mozammel/.FreeCAD/Mod/ose-piping:/home/mozammel/.FreeCAD/Mod/parts_library:/home/mozammel/.FreeCAD/Mod/sheetmetal:/home/mozammel/.FreeCAD/Mod/Render:/home/mozammel/.FreeCAD/Mod/BOLTSFC:/home/mozammel/.FreeCAD/Mod/Reporting:/home/mozammel/.FreeCAD/Mod/fasteners:/home/mozammel/.FreeCAD/Mod/ExplodedAssembly:/home/mozammel/.FreeCAD/Mod/ArchTextures:/home/mozammel/.FreeCAD/Mod/PieMenu:/home/mozammel/.FreeCAD/Mod/WebTools:/home/mozammel/.FreeCAD/Mod/DesignSPHysics:/home/mozammel/.FreeCAD/Mod/dodo:/home/mozammel/.FreeCAD/Mod/Assembly4:/home/mozammel/.FreeCAD/Mod/Curves:/tmp/.mount_FreeCAZEhwqf/usr/bin:/home/mozammel/.local/bin:/usr/local/sbin:/usr/local/bin:/usr/bin:/opt/cuda/bin:/opt/cuda/nsight_compute:/opt/cuda/nsight_systems/bin:/usr/lib/jvm/default/bin:/usr/bin/site_perl:/usr/bin/vendor_perl:/usr/bin/core_perl)
/tmp/.mount_FreeCAZEhwqf/AppRun: line 46: 44975 Aborted (core dumped) "$PREFIX/bin/$name" "$@"
I can't open FreeCAD Linkstage3 branch, both Stable and Daily. But FreeCAD main branch working is fine. It may be a AppImage Issue. Here is the output of terminal when I'm trying to open FreeCAD AppImage
/home/mozammel/Applications/FreeCAD-asm3-Stable-Conda-Py3-Qt5-20210528-glibc2.12-x86_64_76b15da2b46a54d103a358223191e341.AppImage ✔ /tmp/.mount_FreeCAZEhwqf FreeCAD 0.19, Libs: 2021.528R24301 +3572 (Git) Sheet Metal workbench loaded Assembly4 workbench loaded libGL error: MESA-LOADER: failed to open iris: /tmp/.mount_FreeCAZEhwqf/usr/bin/../lib/libstdc++.so.6: version
GLIBCXX_3.4.29' not found (required by /usr/lib/dri/iris_dri.so) (search paths /usr/lib/dri) libGL error: failed to load driver: iris libGL error: MESA-LOADER: failed to open iris: /tmp/.mount_FreeCAZEhwqf/usr/bin/../lib/libstdc++.so.6: version
GLIBCXX_3.4.29' not found (required by /usr/lib/dri/iris_dri.so) (search paths /usr/lib/dri) libGL error: failed to load driver: iris libGL error: MESA-LOADER: failed to open swrast: /tmp/.mount_FreeCAZEhwqf/usr/bin/../lib/libstdc++.so.6: version `GLIBCXX_3.4.29' not found (required by /usr/lib/dri/swrast_dri.so) (search paths /usr/lib/dri) libGL error: failed to load driver: swrast which: no openscad in (/tmp/.mount_FreeCAZEhwqf/usr/bin:/tmp/.mount_FreeCAZEhwqf/usr/Mod/AddonManager:/tmp/.mount_FreeCAZEhwqf/usr/Mod/Arch:/tmp/.mount_FreeCAZEhwqf/usr/Mod/Draft:/tmp/.mount_FreeCAZEhwqf/usr/Mod/Drawing:/tmp/.mount_FreeCAZEhwqf/usr/Mod/Fem:/tmp/.mount_FreeCAZEhwqf/usr/Mod/Idf:/tmp/.mount_FreeCAZEhwqf/usr/Mod/Image:/tmp/.mount_FreeCAZEhwqf/usr/Mod/Import:/tmp/.mount_FreeCAZEhwqf/usr/Mod/Inspection:/tmp/.mount_FreeCAZEhwqf/usr/Mod/Material:/tmp/.mount_FreeCAZEhwqf/usr/Mod/Measure:/tmp/.mount_FreeCAZEhwqf/usr/Mod/Mesh:/tmp/.mount_FreeCAZEhwqf/usr/Mod/MeshPart:/tmp/.mount_FreeCAZEhwqf/usr/Mod/OpenSCAD:/tmp/.mount_FreeCAZEhwqf/usr/Mod/Part:/tmp/.mount_FreeCAZEhwqf/usr/Mod/PartDesign:/tmp/.mount_FreeCAZEhwqf/usr/Mod/Path:/tmp/.mount_FreeCAZEhwqf/usr/Mod/Points:/tmp/.mount_FreeCAZEhwqf/usr/Mod/Raytracing:/tmp/.mount_FreeCAZEhwqf/usr/Mod/ReverseEngineering:/tmp/.mount_FreeCAZEhwqf/usr/Mod/Robot:/tmp/.mount_FreeCAZEhwqf/usr/Mod/Show:/tmp/.mount_FreeCAZEhwqf/usr/Mod/Sketcher:/tmp/.mount_FreeCAZEhwqf/usr/Mod/Spreadsheet:/tmp/.mount_FreeCAZEhwqf/usr/Mod/Start:/tmp/.mount_FreeCAZEhwqf/usr/Mod/Surface:/tmp/.mount_FreeCAZEhwqf/usr/Mod/TechDraw:/tmp/.mount_FreeCAZEhwqf/usr/Mod/Test:/tmp/.mount_FreeCAZEhwqf/usr/Mod/Tux:/tmp/.mount_FreeCAZEhwqf/usr/Mod/Web:/tmp/.mount_FreeCAZEhwqf/usr/Mod/appimage_updater:/tmp/.mount_FreeCAZEhwqf/usr/Mod/asm3:/home/mozammel/.FreeCAD/Mod/A2plus:/home/mozammel/.FreeCAD/Mod/frame:/home/mozammel/.FreeCAD/Mod/Reinforcement:/home/mozammel/.FreeCAD/Mod/fcgear:/home/mozammel/.FreeCAD/Mod/BIM:/home/mozammel/.FreeCAD/Mod/ose-piping:/home/mozammel/.FreeCAD/Mod/parts_library:/home/mozammel/.FreeCAD/Mod/sheetmetal:/home/mozammel/.FreeCAD/Mod/Render:/home/mozammel/.FreeCAD/Mod/BOLTSFC:/home/mozammel/.FreeCAD/Mod/Reporting:/home/mozammel/.FreeCAD/Mod/fasteners:/home/mozammel/.FreeCAD/Mod/ExplodedAssembly:/home/mozammel/.FreeCAD/Mod/ArchTextures:/home/mozammel/.FreeCAD/Mod/PieMenu:/home/mozammel/.FreeCAD/Mod/WebTools:/home/mozammel/.FreeCAD/Mod/DesignSPHysics:/home/mozammel/.FreeCAD/Mod/dodo:/home/mozammel/.FreeCAD/Mod/Assembly4:/home/mozammel/.FreeCAD/Mod/Curves:/tmp/.mount_FreeCAZEhwqf/usr/bin:/home/mozammel/.local/bin:/usr/local/sbin:/usr/local/bin:/usr/bin:/opt/cuda/bin:/opt/cuda/nsight_compute:/opt/cuda/nsight_systems/bin:/usr/lib/jvm/default/bin:/usr/bin/site_perl:/usr/bin/vendor_perl:/usr/bin/core_perl) /tmp/.mount_FreeCAZEhwqf/AppRun: line 46: 44975 Aborted (core dumped) "$PREFIX/bin/$name" "$@"