Your Mac is almost full
The game needs more space than is free.
What happened
Malbec checks the free space before an install or an import, and this one needs more than your Mac has. It stops before it starts, so the disk never fills halfway through.
The fix
Click Open Storage Settings, free space, then start again. Games you no longer play can be uninstalled in their store.
When to write to us
If the sizes Malbec shows look wrong, write to us.
Email support@malbec.app. For a diagnostics file, choose Help › Export Diagnostics… in Malbec and attach the zip it saves. It has no account details, and your home folder is masked.