I use visual studio to update all my environments with a certain migration. It had worked fine using the command below.
update-database -Migration initMigrat
I had the same problem like the reporter of this issue and tried out the recent solution in the Package Manager Console (PMC) and set the environment variable with the command:
$env:ASPNETCORE_ENVIRONMENT='YOUR_ENVIRONMENT'
Unfortunetly I have a ConsoleApplication and use the generic host builder on startup with Host.CreateDefaultBuilder(). In this scenario the environment variable prefix is not ASPNETCORE_ but DOTNET_.
For me this command works in PMC:
$env:DOTNET_ENVIRONMENT='YOUR_ENVIRONMENT'
I want to thank Martin Florin and others to guide me in the correct direction.