Went through this again and seems to be the issue. This should get fixed in the official MonoGame script used in the docs.
After everything done for the installation for Ubuntu 20.04 it did not work. Only after I ran this script which should extract the needed dependencies for mgcb-editor effect compilation (dotnet core 3.1). Just skip all files (type “s” and hit return / enter) when the script asks how to proceed for files that already exist inside the ~/.winemonogame prefix because dotnet core 5 should be there already.
I am on LM 20.2 Uma which is distro which is based on Ubuntu 20.04 and if I see it right, this should not make a difference here)
# check dependencies
if ! type "wine64" > /dev/null 2>&1
echo "wine64 not found"
if ! type "7z" > /dev/null 2>&1
echo "7z not found"
# init wine stuff
mkdir -p "$SCRIPT_DIR"
# get dotnet
curl $DOTNET_URL --output "$SCRIPT_DIR/dotnet-sdk.zip"
7z x "$SCRIPT_DIR/dotnet-sdk.zip" -o"$WINEPREFIX/drive_c/windows/system32/"
Run the script at your own risk. If you want you can also do it by hand. Just download this file
and extract it manually to:
Important: Do NOT replace / override files which already exist!
It may be necessary to run the
command afterwards. After that I could choose mgcb-editor as default application to open files with the mgcb file extension (*.mgcb).