Hi and happy new year 
I changed my SSD and I have some trouble with the new Monogame install.
I followed step by step Getting_started article, but every time I can’t open MGCB editor.
Sometimes I can read to use .Net Core3.1 only, sometimes .Net 5, I am confused.
Thx in advance
Which guide did you follow? and which version are you installing? NuGET version?
EDIT
Also, Happy New Year back
EDIT
Did you not mirror your data or did the previous one die?
Yes sorry, 3.8 version with Visual 2019.
But now, after uninstall all and resintall all without Net Core 3.1, its fine
The previous ssd die 
, all my project are on USB 